Question 11:
Which main group elements have 1 valence electron? 6 valence electrons?
- 1 valence electron: Group 1 (Alkali metals: H, Li, Na, K, Rb, Cs, Fr).
- 6 valence electrons: Group 16 (Chalcogens: O, S, Se, Te, Po).
Question 12:
Determine the group, period, and block for the following elements:
a. \([Ne]3s^1\)
Block: s
Group: 1 (Alkali metals)
Period: 3
b. \([Ar]4s^23d^{10}\)
Block: d
Group: 12
Period: 4
c. \([Ar]4s^23d^{10}4p^2\)
Block: p
Group: 14
Period: 4
d. \([Kr]5s^24d^2\)
Block: d
Group: 4
Period: 5
e. \([Kr]5s^24d^{10}\)
Block: d
Group: 12
Period: 5
Question 13:
Circle the biggest atom based on atomic radii:
a. Ca, Ge, Br, K, Kr
Solution: K (potassium). Atomic radii decrease across a period and increase down a group.
b. Sr, Mg, Be, Ba, Ra
Solution: Ra (radium). Atomic radii increase down a group.
c. F, Cl, Fr, Cs
Solution: Fr (francium). Atomic radii increase down a group.
Question 14:
Circle the atom with the lowest ionization energy:
a. Ca, Ge, Br, K, Kr
Solution: K (potassium). Ionization energy decreases down a group and increases across a period.
b. Sr, Mg, Be, Ba, Ra
Solution: Ra (radium). Ionization energy decreases down a group.
c. F, Cl, Fr, Cs
Solution: Cs (cesium). Ionization energy decreases down a group.
Question 16:
Circle the element with a higher electron affinity (more negative):
a. F or Sn
Solution: F (fluorine).
b. Si or Y
Solution: Si (silicon).
c. Fe or K
Solution: Fe (iron).
d. Bi or N
Solution: N (nitrogen).
e. Ho or Br
Solution: Br (bromine).
f. Rb or Cl
Solution: Cl (chlorine).
Question 17:
Circle the element with a lower electronegativity:
a. F or Sn
Solution: Sn (tin).
b. Si or Y
Solution: Y (yttrium).
c. Fe or K
Solution: K (potassium).
d. Bi or N
Solution: Bi (bismuth).
e. Ho or Br
Solution: Ho (holmium).
f. Rb or Cl
Solution: Rb (rubidium).
Question 18:
Determine the smaller of the following:
a. Ca atom or Ca ion
Solution: Ca ion. Cations are smaller due to loss of electrons and decreased electron repulsion.
b. Cl atom or Cl ion
Solution: Cl atom. Anions are larger due to added electrons increasing repulsion.
c. N ion or O ion
Solution: O ion. Oxygen has more protons, pulling electrons closer.
d. Mg ion or Sr ion
Solution: Mg ion. Smaller due to fewer energy levels.
Question 19:
Which has the most shielding?
a. Br, F, or neither
Solution: Br (bromine). Shielding increases down a group.
b. Al, Cl, or neither
Solution: Al (aluminum). It has more inner electrons.
c. Ca, Ra, or neither
Solution: Ra (radium). Shielding increases down a group.
Question 20:
When sodium becomes an ion:
- Does it lose or gain electrons? It loses electrons.
- How many electrons? 1 electron.
- Nuclear symbol for sodium ion (11 neutrons): \(^ {23}Na^+\).
Question 21:
When aluminum ionizes:
- Does it lose or gain electrons? It loses electrons.
- How many electrons? 3 electrons.
- Nuclear symbol for aluminum ion (14 neutrons): \(^ {27}Al^{3+}\).
Question 22:
When nitrogen becomes an ion:
- Does it lose or gain electrons? It gains electrons.
- How many electrons? 3 electrons.
- Nuclear symbol for nitrogen ion (7 neutrons): \(^ {14}N^{3-}\).
Question 23:
A. An ion with a charge of +2, 20 protons, and 24 neutrons:
- Electrons: 18 electrons.
- Anion or cation: Cation.
- Nuclear symbol: \(^ {44}Ca^{2+}\).
B. An ion with a charge of -2, 18 electrons, and 18 neutrons:
- Nuclear symbol: \(^ {36}S^{2-}\).