Presentation on theme: "Chemical Periodicity Chart"— Presentation transcript:
1 Chemical Periodicity Chart Practice ProblemQuestions and Answers
2 Atomic RadiusP. 178 #16, 2216: How does atomic size change within groups and across periods?Increases down the groups, decreases left-to-right across periods.22: Arrange in order of decreasing size: S, Cl, Al, Na. Is there a pattern?Na, Al, S, ClThis is a period-based trend (left-to-right, n=3).
3 Atomic RadiusP.181 #36A: Which element has a larger radius: Na or Li?NaB: Which element has a larger radius: Sr or Mg?SrC: Which element has a larger radius: C or Ge?GeD: Which element has a larger radius: O or Se?Se
4 Atomic RadiusP. 182 #50Why does fluorine have a smaller atomic radius than oxygen and chlorine?It’s further to the right in oxygen’s period, it’s higher up than chlorine.In other words, “stronger nucleus” than oxygen, fewer electrons than chlorine.
5 Ionization Energy P. 178 #17-18 17: When do ions form? When electrons are added or removed.18: What happens to first ionization energy within groups and across periods?Increases left-to-right across periods, decreases down groups.
6 Ionization EnergyP.178 #23A: Which element has the larger first ionization energy: Na, K?NaB: Which element has the larger first ionization energy: Mg, P?P
7 Ionization EnergyP.181 #37, 3837: Explain the difference between first and second ionization energy:First i.e. = energy to remove one electron.Second i.e. = energy to remove a second electron38: Which element has a greater first i.e.?Li, BBMg, SrMgCs, AlAl
8 Ionization EnergyP. 181 #39Arrange the groups of elements in order of increasing ionization energy:Be, Mg, SrSr, Mg, BeBi, Cs, BaCs, Ba, BiNa, Al, S
9 Ionization EnergyP.181 #40Why is there a large increase between the first and second ionization energies of the alkali metals?After removing the first electron, the second electron is in a lower (closer) energy level (lower n number).
10 Ionization EnergyP. 182: 51, 5551: Would you expect metals or nonmetals in the same period to have higher i.e.?Nonmetals – they’re further right (“stronger nuclei”)55: Which equation represents the first ionization of an alkali metal atom?A: Cl Cl+ + e-B: Ca Ca+ + e-C: K K+ + e-D: H H+ + e-
11 Ionization EnergyP. 182: 51, 5551: Would you expect metals or nonmetals in the same period to have higher i.e.?Nonmetals – they’re further right (“stronger nuclei”)55: Which equation represents the first ionization of an alkali metal atom?A: Cl Cl+ + e-B: Ca Ca+ + e-C: K K+ + e-D: H H+ + e-
12 Ionization EnergyP.182 #58Why is there a large jump between the second and third ionization energies of magnesium? Why is there a large jump between the third and fourth ionization energies of aluminum?Those last electrons are in closer energy shells (lower n number).
13 Ionic SizeP. 178 #19Compare the size of ions to the size of their neutral forms.Cations lose electrons, become positively charged, get smaller.Anions gain electrons, become negatively charged, get larger.
14 Ionic SizeP. 181 #41, 4241: How does the ionic radius of a typical metal compare with its atomic radius?Metals tend to lose electrons so their ionic radii get smaller.42: Which particle has a larger radius in each atom/ion pair?Na, Na+NaS, S2-S2-I, I-I-Al, Al3-Al
15 Ionic Size P. 182: #52 In each pair, which ion is larger? Ca2+, Mg2+ Cl-, P3-P3-Cu+, Cu2+Cu+
16 Ionic SizeP. 182 #59The bar graph shows the relationship between atomic and ionic radii for Group 1A elements. A: Describe the trend in atomic radius. B: Explain the difference between ionic and atomic radius size?A: Radius increases as you go down a group.B: Ions are smaller due to fewer electrons than in the neutral atom (atomic radius).
17 Ionic SizeP.183 #64, 6564: The Mg2+ and Na+ ions each have ten electrons. Which is smaller and why?Mg2+ is smaller because though it has ten electrons just like Na+, it has more protons. They pull “harder” on the electrons.65: How do you expect the radii of S2-, Cl-, K+, Ca2+, and Sc3+ to vary – they have the same total electrons as the noble gas Argon. What about for O2-, F-, Na+, Mg2+, and Al3+, which is the same as Neon?Radius decreases from left to right across a period in both cases. Though electron # is the same, proton number goes up.
18 Ionic SizeP. 183 #68Atoms and ions with the same number of electrons are isoelectronic.Write the symbol for a cation and anion that are isoelectronic with Krypton:Br-, Rb+, Se2-, As3-, Sr2+ (each have 36 electrons)Can you have an isoelectric cation and anion in the same period?No, cations lose electrons but anions (higher overall number of electrons) gain them.
19 ElectronegativityP. 178 #20How does electronegativity vary within groups and across periods?Increases across period left-to-right.Decreases down groups.
20 ElectronegativityP.181 #43A: Which element has a higher electronegativity value: Cl, F?FB: Which element has a higher electronegativity value: C, N?NC: Which element has a higher electronegativity value: Mg, Ne?Mg [Ne does not react]D: Which element has a higher electronegativity value: As, Ca?As
21 ElectronegativityP.181 #44Why are noble gases not given electronegativity values?Electronegativity only applies in compounds. Noble gases don’t react and form compounds.