Resource 1 Electron Configuration of Ions

Chapter 7 Resource Worksheets KEY Resource 1: Electron Configuration of Ions 1. Write electron configurations for the following ions: Electron Configuration Ion K+ F- 1s2 2s2 2p6 3s2 3p6 1s2 2s2 2p6 S2Ni2+ Al3+ 1s2 2s2 2p6 3s2 3p6 1s2 2s2 2p6 3s2 3p6 3d8 1s2 2s2 2p6 Cu2+ ClPb4+ 1s2 2s2 2p6 3s2 3p6 3d 9 1s2 2s2 2p6 3s2 3p6 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 4f14 5d10 N3Fe3+ Zn2+ Sc3+ 1s2 2s2 2p6 1s2 2s2 2p6 3s2 3p6 3d5 1s2 2s2 2p6 3s2 3p6 3d10 1s2 2s2 2p6 3s2 3p6 Ag1+ Ni3+ 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1 4d9 1s2 2s2 2p6 3s2 3p6 3d7 2. Identify which of the following ions from Question 1 have noble gas or pseudo-noble gas configurations. Noble gas: K+, F-, S2-, Al3+, Cl-, N3-, Sc3+ Pseudo-noble gas: Pb+4 3. For the following electron configurations choose 3 possible elements (or ions) they may represent 2 2 6 2 6 2 10 4 Kr, Br-, Se2-, As3-, Sr2+, Rb+ a) 1s 2s 2p 3s 3p 4s 3d 4p 2 2 6 2 6 2 10 6 2 10 6 2 14 10 6 1 b) 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s Kr, Rn-, At2-, Po3-, Ra+ 2 2 6 2 6 2 10 6 2 10 6 2 14 10 4 c) 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p Po, Bi-, Rn2+, At+ 2 2 6 2 6 2 5 d) 1s 2s 2p 3s 3p 4s 3d Mn, Fe+ , Co2+, Ni3+ 2 2 6 2 6 2 10 6 2 10 2 e) 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p Sr, Rb-, Kr2-, Zr2+, Y + 1 22+ + f) [Ar] 4s K, Ar , Cl , Sc , Ca g) [Ne] 3s2 3p1 Al, Mg-, Na2-, P2+, Si+ 4. Determine which of the following electron configurations are valid. a) 1s2 2s2 2p6 3s2 3p6 4s2 4d104p5 not valid (take a look at “4d”) b) 1s2 2s2 2p6 3s3 3d 5 not valid (3p comes after 3s) c) [Ra] 7s2 5f8 not valid (radium isn’t a noble gas) d) [Kr] 5s2 4d 10 5p5 valid e) [Xe] not valid (an element can’t be its own electron configuration) 1 Chapter 7 Resource Worksheets KEY Resource 2: Atomic Radii and Isoelectronic Series 1. In each of the following sets, which atom has the smallest radius. a. H or He b. Na or Cl c. Cl or In or Se d. element 120 or element 119 or element 116 2. Arrange the following groups of atoms in order of increasing size. a. Te, S, Se (smallest) S < Se < Te (largest) b. K, Br, Ni (smallest) Br < Ni < K (largest) c. Si, Ba, F (smallest) F < Si < Ba (largest) d. N, Sb, P, Bi, As (smallest) N < P < As < Sb < Bi (largest) e. C, Al, O, K (smallest) O < C < Al < K (largest) 3. In each of the following pairs, circle the species with the larger atomic radius: a. Mg or Ba 2- b. S or S +2 c. Cu or Cu d. H + or H or H e. Na- or Na or Na+ 2– – f. S or Cl or Cl 4. Arrange in order of increasing radius a. F- , Na+ , O2-, Mg2+, N 3(smallest) Mg2+ < Na+ < F- < O 2- < N35. Of the following species (Sc, Ca2+, Cl, S2-, Ti3+), which are isoelectric? [Ar]; note that Ti3+Tand Sc both end in 3d 1 , however, Ti3+ does not have 4s electrons. 6. For each ion listed, write a neutral atom and an ion with the indicated charge that would be isoelectronic. Circle the largest one for each row. Neutral Atom a) FCa2+ b) c) B3+ d) Cl- e) S2f) Al3+ Charge Charged Atom Ne +1 Na+ Ar He Ar Ar -2 -1 +1 +1 S2- Ne +3 N3- HK+ K+ 7. Describe what causes the observed trend in atomic radii for a group? Atomic radius increases down the group on the periodic table because the outermost electrons are found in the valence shell that is farther away from the nucleus which increases the number of core electrons (increases the shielding effect) resulting in reduced attraction between the nucleus and the outermost electrons. 8. Why are cations smaller than parent atoms and anions bigger than parent atoms? 2 Chapter 7 Resource Worksheets KEY Resource 4: All Periodic and Group Trends 1. Circle the elements in each list that would have the most similar chemical reactivity. a. C N F Si Pb b. P As F S N c. Y K Ba Ca Ar d. Mg Cs Li Na Ar 2. Why do elements in the same family generally have similar properties? Because they have same number of electrons in the outer shell (valence electrons) which take part in chemical reaction. 3. Indicate whether the following properties increase or decrease left to right across a period a. atomic radius (excluding noble gases) Decreases b. first ionization energy Increases c. electron affinity Increases Down a group Increases Decreases Decreases 4. Circle the best choice in each list: a. highest first ionization energy: C, N, Si b largest radius: C4-, C4+, C c. highest electron affinity: As, Sn, S d. smallest atom: Na, Li, Be e. lowest first ionization energy: K , Na, C 5. For the following pairs of atoms or ions, fill in the blank with either < or > to correctly order the identified periodic trend. a. Atomic radius Si Br Au Mg > Cl > Cl < Hf < Na b. Ionic Radius K+ < Cs F- > Ne Ar > K+ Al3+ < N3- c. Ionization Energy Na > He > N < Al > d. Electron Affinity Cl > I Na < Mg K H O Mg O < F H < He 4