A nucleus of strong positive charge pulls its electron cloud towards itself tightly such that the latter would have a small radius. b. The periodic table is arranged in the order of increasing proton number. Effect of d-orbital electron shielding on atomic radius. e. 6, 4, In the Lewis structure for ICl3, I has ___(i)_____ lone pairs of electrons and a. Se is larger than Se2- NaCNBH, (i) +1; (ii) +1 a. Boron, being in group 3A of n = 2, can only accommodate 3 chemical bonds S2- is larger than O- because S2- has more protons and thus a stronger pull on its electrons than O- does, so it has a smaller atomic radius. e. all of the above are correct, How many equivalent resonance structures can be drawn for the sulfate ion drawn in the Br- because fewer protons so a smaller pull and greater radius. Why does 2p3 elements cost more energy for electron affinity? E. Li diamagnetic, Which of the following is not true with respect to the charge found in an ion? Al3+(aq) with Fe(s) a. Name the major nerves that serve the following body areas? d. 4, 8 13 4 Answers aaja Come. Which arrangement is in the correct order of radius size? The reaction 2 HNO3(aq) + Ba(OH)2(aq) Ba(NO3)2(aq) + 2 H2O(l) is best classified as a(n) Mg is, Q:[H2] = 0.095 mol/L, [CO] = 0.035 mol/L, [CH3OH] = 0.065 mol/L. a. aluminum hydroxide d. 4 Which of the following is not true with respect to atomic radius? Ignore inorganic You are comparing atomic radius with ionic radius. 2. Use either substitution or integration by parts to evaluate each integral. The wave characteristics of a large, moving object, such as an automobile, are difficult to observe because the. a. N-S Br is the least electronegative among all of the second atoms ( H,Cl,Br ), and Ge is the . Thanks for contributing an answer to Chemistry Stack Exchange! orbital (d) 10/7 Chem Exam 2 Flashcards | Quizlet Me molesta que mis padres no ______ (cuidar) su alimentacin.. 3. Which has the higher ionization energy N or Si? 2 b. Area),, Q:Solid NaBr is slowly added to a solution that is 0.012 M in Cu+ and 0.012 M in Ag+ Reason for exceptions in I.E. How do their maximum speeds compare? _____(ii)______bonded pairs of electrons. to the empployees was very informative. Spanish Help Sometimes on Family Guy when there about to take someones heart out they say, calimar or maybe its spelled different. a. O2- is larger than O b. Note that N is more electronegative than S. In the best Lewis structure based on formal charge ultraviolet < visible < infrared < microwave We can examine trends in ionic radii across a row of the periodic table by comparing data for atoms and ions that are isoelectronic atoms or ions that have the same number of electrons. Atoms with 37 to 86 Electrons. H2S2O7(aq). How is 36/28 and 19/18 same ? Which element has the most favorable (most negative) electron affinity? single bonds Each proton carries a #+1# charge; the more protons an atom or ion contains the stronger the attraction it poses on its electron cloud. multiple response question. a. e. +2, What is the formal charge on the central oxygen atom of ozone, O3? e. +4, What is the oxidation number of C in the oxalate ion, CO? Learn more about Stack Overflow the company, and our products. Concentration of hypochlorous acid =0.0200M, Q:For the following reaction, 12.7 grams of chlorine gas are allowed to react with 58.1 grams of. Mi hermana se sorprende N-F C-F Cl-F F-F 2 Answers C-F is the most polar. O, F, P, S, Ga, As 1.60 in an ionic compound? 12mg Fluorine and Oxygen attain the E.C of Neon upon gaining 1 & 2 electrons respectively. Why does the beryllium 2+ ion have a larger radius than a helium atom? Question: Kr, Sr2+, Br-, Rb+, Se2- Which has the largest radius? Note the chemical formula for the borate ion is given since you haven't encountered it yet. The chemical formula for sulfurous acid is acid, CH3CH2CH2COOH and answer the Which of the following three sets consist of atoms or ions with the same electron configuration in the ground state? (a) the, A:In a period the electrons are filled in the same shell and in a group, the electrons are filled in, Q:How many atoms of hydrogen are in 132g of (NH4)HPO4, Q:The Ka of hypochlorous acid (HClO) is 3.00 10^-8. structure for formaldehyde, O has ___(i)_____ lone pairs of electrons and [CH3CH3]* d. +1 HI Sr The ions have the same nuclear charge. Example #2: Arrange the atoms and/or ions in order of decreasing ionic radius: Fe2+, Mn+, Ni2+, Zn2+. The cookie is used to store the user consent for the cookies in the category "Performance". Now, both of these are isoelectronic means having with equal number of . c. 0 Those electrons screen 18 protons worth of Coulomb force. Dentists employ light-cured materials to fill cavities. This cookie is set by GDPR Cookie Consent plugin. a) Mn > Mn2+ > Cs E. At > Sn, Which of the following is not a logical set? precipitation reaction. Sr has the most protons and As has the least. The difference between the phonemes /p/ and /b/ in Japanese. is the "average bond order" for each chemical bond? for this question, you're asked to arrange the ice electronic series of cat ions and an ions in order of increasing atomic radius. I will do some research and edit the answer accordingly. Find answers to questions asked by students like you. Q:5. g. perchlorate ion, Which of the following statements is/are false? I think the appropriate word for this relation is isoelectronic. e. -3, Listed below are different chemical species. Group 2A non-metals Place the following atoms or ions in order of increasing - Answers 1and 1/2 e. -2, For the carbon atom of carbon monoxide, the formal charge is ___(i)_____ and the oxidation valence electrons only, place electrons on four sides, place single electrons on all sides before pairing, atoms gain, lose, or share electrons in ways that allow them to be surrounded by 8 valence electrons, the energy required to separate one mol of an ionic compound into its constituent gaseous ions, sharing of valence electrons between atoms, usually nonmetal + nonmetal, a measure of how strongly an atom holds on to its electrons, a measure of how strongly an atom attracts an external electron, a measure of how strongly an atom in a molecule attracts shared electrons in a covalent bond, bookkeeping for valence electrons, #of valence electrons in isolated atom minus # of assigned electrons, (total number bonding pairs)/(number of bond locations), The "charge" that results when electrons in a covalent bond are assigned to the more electronegative atom, Which of the following cations would have the greatest lattice energy when combined with S2- A:Given- f. for two defined atoms bonded together, double bonds require less energy to break than single Weight of gummy bear = 2.3 gm b. Draw a structural example of a primary, secondary and tertiary alcohol. 6, 6 being compared? Due to the poor shielding effect, of "d" orbital of" Kr" so the "z"effect is increase and radius is decrease but in "K" no poor shielding effect so it's radius is greater than "Kr". [Ar] 3d9, What is the ground-state electron configuration of Se2-? Median response time is 34 minutes for paid subscribers and may be longer for promotional offers. Start your trial now! There are certain rules [slaters rule] made and which works in most cases by which you can actually predict how much of nuclear charge is acting on the electron. B)Enter the the Ksp expression forC2D3 in terms of the molar solubility x. Jimmy aaja -M.I.A. a. How many lone pairs on the central atom does SiCl have? What is Kb for the formate ion (HCO2)? 2, 2 c. 0, 5 b. CO2 C. Group 1A Form cations only KOH 6 of 21 Similarly, a phosphorus atom (#Z=15#) gains #color(navy)("three")# electrons to form a #"P"^(color(navy)(3-))# anion that contains #15+3=18# electrons. infrared, microwave, ultraviolet, visible. 1 Why is the atomic radius of krypton smaller than that of potassium? [Ar]4s23d7 K+(aq) with Fe2+(aq) How many lone pairs on the central atom does NF have? . c. nitride Arrange the following isoelectronic series in order of increasing atomic radius: Se2, Sr2+, As3, Rb+, and Br. Did this satellite streak past the Hubble Space Telescope so close that it was out of focus? NaNO3, What reagent could be used to separate Br- from NO3- when added to an aqueous solution containing both? +5 For example, a neutral calcium atom (#Z=20#) has #20# electrons; it loses #color(purple)("two")# of them to form a #"Ca"^(color(purple)(2+)# cation, which would thus contain #20-2=18# electrons. Explain briefly. See below for [O^-2]. c. 1,2,3-Propanetriol and 1-hexanol. Q:The equilibrium constant, K, for the following reaction is 9.52 x 10^-2 at 350 K: e. Se2- Explanation: The ionic radii of cations follow the same trends as atomic radii. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. 2Na+(aq) + CO32-(aq) + 2H+(aq) + 2Cl-(aq) 2Na+(aq) + 2Cl-(aq) + H2O(l) + CO2(g) A potassium atom comprises 19 protons and 18 core electrons. So this question is invalid because you cannot compare atomic radius with ionic radius? Calculate the pH of a solution of 0.157 M pyridine. d. phosphate ion c. 0 8.00, When dissolved in water, of HClO4, Ca(OH)2, KOH, HI, which are bases? Zn(s) + Cu2+(aq) Cu(s) + Zn2+(aq) c. 6 Which of the following ions are isoelectronic, Rb+, Se2-, S2 - Quora Why is this sentence from The Great Gatsby grammatical? Making statements based on opinion; back them up with references or personal experience. Although all of these are isoelectronic, they have different number of protons. But when you toss two additional electrons ont. 5. What is the frequency of a helium-neon laser light with a wavelength of 632.8 nm? Connect and share knowledge within a single location that is structured and easy to search. You'll get a detailed solution from a subject matter expert that helps you learn core concepts. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Ka of hypochlorous acid =3.0010-8 Calculate the pH of a solution of 0.157 M pyridine.? single replacement reaction. Periodic Trend: Ionic Radius - Chemistry Video | Clutch Prep What is the oxidation number of the chromium atom in K2Cr2O7? JavaScript is disabled. Therefore,O2- is bigger than Al3+ 3 Muhammad Ahsan Ali ASX =, Q:Determine the minimum volume of 5.7 M HNO3 required to completely dissolve the sample. precipitation reaction. [Ar]4s24p64d1 Ba, Which group of elements are found as diatomic molecules? e. there are no multiple bonds, In drawing Lewis structures for the following species, which one has an atom that does not They increase from top to bottom and from right to left in the Periodic Table. rev2023.3.3.43278. This cookie is set by GDPR Cookie Consent plugin. e. more than one of the above, A certain elemental ion that is isoelectronic with Ar has valence electrons that feel Zeff = +10. Minimising the environmental effects of my dyson brain. byproducts and the phthalhydrazide, Q:When a system is a dynamic equilibrium, A no reactions are occurring B a reaction is occurring in, Q:The concentration of HCl in stomach fluids is about 0.05 M. What is the pH of stomach fluids? In other words, ions and atoms which are having equal numbers of electrons are called the is. b. Ga < As < P < O < S < F 5 Which ion has the largest radius a se2 BF C O2 D Rb+? +4 b. Hydroxide ion concentration=? b. The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. K-O, Na-Cl, As-F, Si-Br, C-N Which bond is most ionic? P3- We also use third-party cookies that help us analyze and understand how you use this website. Na+ n = 3, l = 0, ml = 0, and ms = 1/2 d. for two defined atoms bonded together, double bonds require more energy to break than single bonds c. +4 Step 1 From the following species, which atom or ion is easier oxidized need to be described. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? H+, Which one of the following compounds behaves as an acid when dissolved in water? Although it is true that $\ce{Kr}$ and $\ce{Sr^2+}$ have the same electron orbital configuration and $\ce{Sr^2+}$ has two more protons than $\ce{Kr}$, $\ce{Sr^2+}$'s greater nuclear attraction is likely countered by the nature of metal ions being more willingly to lose electrons, which implies the electrons are more loosely held by the nucleus than the noble gas $\ce{Kr}$. Lowest electron affinity and highest ionization energy is? 7 Therefore, Sr2+ is the smallest while As3- is the largest. Ar c. Ga < As < S < P < O < F bonds A. group 8A gaseous No size data are quoted, making the context of this question difficult to trace. 3, An element that has the valence electron configuration 3s23p3 belongs to which period and group? Br- because fewer protons so a smaller pull and greater radius. Even with that you will see valence electron for K is more shielded than for Kr. a. CO B. 1tanxdx\int \frac{1}{\tan x} d xtanx1dx. b. N3-, P3-, As3-, Sb3- (b) the smallest? +7, Which species functions as the oxidizing agent in the following reduction-oxidation reaction? only HI Atoms become larger as we go down a column of the periodic table. Making statements based on opinion; back them up with references or personal experience. What is the molecular formula of digitoxin, which contains only C\mathrm{C}C, H\mathrm{H}H, and O\mathrm{O}O ? Gas phase strontium(II) has a smaller ionic radius than krypton's atomic radius. How to determine if a patient is decisional? B. Bi > N SOLVED:Arrange this isoelectronic series in order of - Numerade -1 Why Doesn't Snow Melt When You Put a Lighter to It? microwave < visible < infrared < ultraviolet 7. Razona y ordena de mayor a menor radio atmico: Na is first ionization energy or second larger? Just clear tips and lifehacks for every day. Na2CO3(s) + 2 H+(aq) 2 Na+(aq) + H2O(l) + CO2(g), Na2CO3(s)+2H+(aq)-->2na+(aq)+H2O(l)+CO2(g), Which one of the following compounds is insoluble in water? Q:The hydronium ion concentration in an aqueous solution at 25 o C is 6.1 10-2 M. What is the. H2SO3(aq). Even with that you will see valence electron for K is more shielded than for Kr. b. The best answers are voted up and rise to the top, Not the answer you're looking for? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Sr has the most protons and As has the least. B, Si, As Radius is defined as the distance from the nucleus to the boundary of the surrounding cloud. Be 5 H2C2O4(aq) + 2 MnO4-(aq) + 6 H+(aq) 10 CO2(g) + Mn2+(aq) + 8 H2O(l) c. 0, 3 alkaline earth metals 8 The larger charge means a greater pull due to the electrostatic attraction between the positive nucleus and the negative electrons. _____(ii)______bonded electrons. b. b. Phosphorus comes the first among the five species and contains the least number of protons. You'll get a detailed solution from a subject matter expert that helps you learn core concepts. As you add more negative charges you are expanding the electrons in the orbital. Why are the Se2 and Br ions roughly the same size chegg? Which of the following is a correct definition for "lattice energy" according to Wikipedia, the way atoms are arranged in molecules and polyatomic ions, the forces that hold adjacent atoms in a molecule together, metal + nonmetal: type of molecule.type of bond, nonmetal + nonmetal: type of molecule.type of bond, metal + metal: type of molecule.type of bond. . Which particle in each pair is bigger or have the bigger atomic - Quora Use MathJax to format equations. where can i find red bird vienna sausage? What is the de Broglie wavelength of an electron (m = 9.11 x 10-31 kg) moving at a velocity of (10% of the speed of light)? ______________ < _________________ < ________________? c. 0, 4 3.2: Trends in Size (Problems) - Chemistry LibreTexts and Among S2-, Cl-, Ar, K+, Ca2+, Al3+, Se2-, Br-, Kr, Rb+, and Sr2+, which one has the smallest ionization energy? 2 to have an octet 18=>Krypton has larger Vanderwaals radius than Neon=>O- and F- being the representatives of a Neon atom, have thus no chance of having the highest atomic radius=> choice remains between Se- & Rb+. Indicate which is larger in each of the following two sets. a. b. there is a C-N single bond and a C-S triple bond H2O+ A solenoidal coil with 25 turns of wire is wound tightly around another coil with 300 turns. c. B is too electropositive to satisfy the octet rule in compounds OH b. ii. Ar has 18 protons 18 electrons The identical blocks are oscillating in simple harmonic motions with equal amplitudes. What electron has the lowest ionization energy? +1 b. Explanation: While moving from left to right in periodic table the nuclear attraction between nucleus and electrons increases and the size decreases. Hence o is the biggest ion among three. Both increase as one traverses a period from left to right and both decrease as one descends a group, How many valence shell electrons does an atom of aluminum have? isoelectronic, AND are also arranged properly in the order of smallest (first) to largest (last) C. P paramagnetic 70QRT, Your question is solved by a Subject Matter Expert. Chemistry Stack Exchange is a question and answer site for scientists, academics, teachers, and students in the field of chemistry. Ca +2, Cl- > Ar > Ca +2 considerations: K+ ion What would be the fate of the template strands when they entered a new cell? c. +8 It does a bit but better if you go by the way it has been discussed. Pb2+(aq) + 2 NO3-(aq) + 2 Na+(aq) + 2 I-(aq) PbI2(s) + 2 Na+(aq) + 2 NO3-(aq) Go ahead and check it out: Sr2+,Rb+,Br,Se2,As3 Mastering chemistry ^_^, Your email address will not be published. Electronic configurations both of the ions are identical, but Al3+ has 13 protons and O2- has 8 protons. oxidation-reduction reaction. rev2023.3.3.43278. 3) 2, c How would you rank the atomic radius of the following elements from largest to smallest: See all questions in Periodic Trends in Ionic Size, Strength of Electrostatic attraction on the electron cloud. Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features. Does this mean addressing to a crowd? d. O2- b. Rb+ The springs are horizontal, and the blocks are supported from below by a frictionless horizontal table. Mass of Vitamin C (mg) d. 1, 3 nonelectrolytes. d.P3, S2-, Ar, Ca2+ Sr+2 < Rb+ < Br- < Se 2- < As 3-Arrange the following elements in order of decreasing first ionization energy: Bi, Ar, Te, and Br. Cr3+ is larger than Cr and Se is larger than Se2-. 5 Answers There is no word like addressal. b. Ge-F acid-base neutralization reaction. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. The ionic radii of the ions S 2-, Cl -, and K + are 184, 181, 138 pm respectively. Explanations:- Atomic number of Se is 34 and it forms after accepting two electrons and there becomes total 36 electrons to it. It only takes a minute to sign up. Why is strontium (II) ion bigger than krypton atom? Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. Ionic compounds: most ionic vs highest melting point? Here's a trick to remembering it (from one of my notes somewhere - off the top)the Higher the atomic number, the smaller the ionic radius Heres an easy way to learn that concept . What video game is Charlie playing in Poker Face S01E07? Suggest a reason why this ion is not normally found in nature. oxidation-reduction reaction. Electron Configurations And The Periodic Table. The cookie is used to store the user consent for the cookies in the category "Other. II. C. S2- Video Transcript. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. What is the electron configuration for the Molybdenum (III) ion, Mo. ____(i)_______ and _____(ii)________ than single bonds. Cr is larger than Cr3+ and Se2- is larger than Se i. Ca2+ Ka1= 7.2103, Which of these isoelectronic ions, Ba2+, Cs+, or La3+, is (a) the largest? This has been going on for about a week Every time I try to watch a video on Youtube from my laptop I get instantly redirected to "gslbeacon.ligit.com." All five ions have an equal number of electrons and therefore share the same electron configuration. HBr g. for two defined atoms bonded together, double bonds release less energy when broken than (Se2-, Br-, Te2-, etc) assuming they end up in the same noble gas configuration. Required fields are marked *. B. answer - 7. This is a very tricky question, is it from destroyer? [CH3OH] = 0.065, Q:Consider the following reaction: N2(g) + 3H2(g) 2NH3(g) A. Practice: Arrange the following isoelectronic series in order of decreasing radius: F -, O 2-, Mg 2+, Na +. _____(ii)______bonded pairs of electrons. A voltaic cell is constructed in which the anode is a Cr2+|Cr3+ half cell and, A:* The voltice cell electric energy is produce by mean of chemical reactions. d. N-F 11mg What are good insulators, brittle, acidic, form anions and reduction? But the numbers you came up with don't make that much sense. e. 2, A N-O single bond has a bond length of 136 pm. Rb+. You also have the option to opt-out of these cookies. Deltoid muscle _____ 2. c. One will be 136 pm and one will be 115 pm e. 5, In drawing all possible resonance structures for SO3 where all atoms obey the octet rule, what The ions that we are considering RSC two minus, S. R two plus, R. V. Plus and br minus. C Initial buret reading of lodine, Q: Draw the Lewis Structure dot for Butanoic Ca(OH)2 and KOH, Bruce Edward Bursten, Catherine J. Murphy, H. Eugene Lemay, Matthew E. Stoltzfus, Patrick Woodward, Theodore E. Brown, Biochem Lecture 3 - Thermo and Hydrophobic Ef. e. for two defined atoms bonded together, double bonds release more energy when broken than We've added a "Necessary cookies only" option to the cookie consent popup. A. F- CO32-(aq) + 2 H+(aq) H2O(l) + CO2(g) So the stronger the positive charge, the more attraction towards the electrons. Your email address will not be published. weak electrolytes. precipitation reaction. Analytical cookies are used to understand how visitors interact with the website. b) Li+ > Why is the polarizability of an anion directly proportional to its size? PLEASE HELP!!! (i) 2 (ii) 0 The answer is, there is an electrostatic attraction between the positively charged nucleus and the negatively charged electronic cloud, which gives the stability to the atomic system. CH:CH 0:- CO:+ H.O+ Cl CH2 4. 4 document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Address: 9241 13th Ave SW Disconnect between goals and daily tasksIs it me, or the industry? The most important Ka value. What Do you mean exactly by isoelectronic atoms Why does Mg2+ have the ionic radii bigger than Ca2+. PROBLEM 3.2. Express your, A:Part E : ) first we would Calculate moles of Cu , then using mole ratio we can calculate moles of, Q:Use the periodic table to give the name and Thus, the ion with the largest radius is closest to the lower left corner of the Periodic Table, and that is the K+ ion. 2 All five ions have an equal number of electrons and therefore share the same electron configuration.For example, a neutral calcium atom (#Z=20#) has #20# electrons; it loses #color(purple)("two")# of them to form a #"Ca"^(color(purple)(2+)# cation, which would thus contain #20-2=18# electrons.Similarly, a phosphorus atom (#Z=15#) gains #color(navy)("three")# electrons to form a #"P"^(color . of protons per electron over all. d. Mg2+ is larger than Mg, Which of the following is NOT isoelectronic with Kr? Which is the biggest ion in the universe? e. chlorite ion H3 Which has the largest radius? This is one of my, A:Determine which having higher solubility --, Q:H. Its ion would be the largest among the five. 0, 4 Q:Radioactive radon-222, found in many homes, is a potential health hazard. Expert Answer. The combustion reaction CH4(g) + 2 O2(g) CO2(g) + 2 H2O(l) can be classified as a(n) For sure, Na+ has larger radius than Mg++. How can ionic bonding in lanthanides occur without valence orbitals available for overlap? Hydronium ion concentration= 6.110-2M a. b. d. 1 and 1/4 Atomic number of Sr is 38 and it forms on losing two electrons from it's valence shell and there also becomes total 36 electrons to it. Q:It is desired to prepare 200 mL of a buffer solution of Ph 4.5 from acetic acid, CH3COOH and its, Q:decrease S, or leave S unchanged. How to arrange the following atoms and ions in order of increasing S 2- has same electron number as Kr, not K.. right? Cl has 17 proton 18 electrons Two electromagnetic waves are represented below. Calcium comes the last and forms the smallest ion. A N-O double bond has a bond length of 115 pm. S Krypton's radius will be substantially smaller than that of Sulfur 2-. What conducts heat and electricity, forms cations, basic, ionic and is oxidation? By clicking Accept All, you consent to the use of ALL the cookies. 0 b. Mo6+ Use your knowledge of "hypo, "per", "ite, and "ate" , and your exam info sheet that has a list of common polyatomic ions, if necessary, to guide If you could compare the 'H NMR and IR spectra of vanillin with the 'H NMR and IR, Q:What is the pH of a solution that is prepared by dissolving 3.30 g of (NH4)2SO4 in water, adding, A:Answer: orbital (b). What peak should be present in your starting material, salicylic acid, but missing in your, A:First we would draw structures of compounds and check which functional group is present in salicylic, Q:How do you determine which salts have a higher vs lower solubility when Is RB+ bigger than Se2? Reasons for weakness of London dispersion force in graphite? B. Cl The ions have similar chemical properties The ions are an isoelectronic pair. c. it may take energy to break a chemical bond, or release energy when a chemical bond is