Question

periodic trends - review problems

1. put the elements in order from the smallest atomic mass to the largest atomic mass.

a) li, ar, ne
b) p, s, mg
c) ge, i, sb

1. put the elements in order from the smallest atomic radius to the largest atomic radius.

a) k, fr, cs
b) c, ba, n
c) te, s, sn

1. put the elements in order from the smallest to largest ionization energy.

a) ne, be, o
b) ca, sr, f
c) he, ne, xe

1. using your trends, circle the element with the largest atomic mass.

a) li, na, fr
b) na, al, si

1. using your trends, circle the element with the largest atomic radius.

a) be, sr, ba
b) cl, i, f

1. put the elements in order from the smallest electronegativity to the largest electronegativity.

a) zr, zn, al, co
c) ba, y, al, cl
b) ca, ne, br, ar
d) i, f, br, ne

1. put the elements in order from the smallest to the largest reactivity.

a) f, p, cl, s
c) fr, mn, cr, rb
b) mg, na, be, cs
d) c, b, o, n, f

Explanation:

Step1: Recall atomic - mass trends

Atomic mass generally increases as we move down a group and across a period in the periodic table. For a) Li (6.94), Ne (20.18), Ar (39.95), so the order is Li, Ne, Ar. For b) Mg (24.31), P (30.97), S (32.07), so the order is Mg, P, S. For c) Ge (72.63), Sb (121.76), I (126.90), so the order is Ge, Sb, I.

Step2: Recall atomic - radius trends

Atomic radius increases down a group and decreases across a period. For a) K, Cs, Fr are in the same group and the order of increasing atomic radius is K, Cs, Fr. For b) C and N are in the same period (C > N in radius as we move left - to - right), and Ba is in a lower period, so the order is N, C, Ba. For c) S, Te are in the same group (S < Te in radius as we move down), and Sn is in a different group, so the order is S, Te, Sn.

Step3: Recall ionization - energy trends

Ionization energy generally increases across a period and decreases down a group. For a) Be (lowest as it is in Group 2), O (higher as it is in Group 16), Ne (highest as it is a noble gas), so the order is Be, O, Ne. For b) Ca and Sr are in the same group (Ca > Sr in ionization energy), and F is in a different group with a high ionization energy, so the order is Sr, Ca, F. For c) He, Ne, Xe are noble gases and the order is Xe, Ne, He.

Step4: Identify element with largest atomic mass

For a) Li (6.94), Na (22.99), Fr (223), Fr has the largest atomic mass. For b) Na (22.99), Al (26.98), Si (28.09), Si has the largest atomic mass.

Step5: Identify element with largest atomic radius

For a) Be, Sr, Ba are in the same group and Ba has the largest atomic radius. For b) Cl, I, F are in the same group and I has the largest atomic radius.

Step6: Recall electronegativity trends

Electronegativity increases across a period and decreases down a group. For a) Al (1.61), Co (1.88), Zn (1.65), Zr (1.33), the order is Zr, Al, Zn, Co. For b) Ca (1.00), Ne (not applicable as noble gas), Ar (not applicable as noble gas), Br (2.96), we consider only Ca and Br, so the order is Ca, Br. For c) Ba (0.89), Y (1.22), Al (1.61), Cl (3.16), the order is Ba, Y, Al, Cl. For d) I (2.66), F (3.98), Br (2.96), Ne (not applicable as noble gas), the order is I, Br, F.

Step7: Recall reactivity trends

Reactivity of non - metals increases across a period and decreases down a group, and for metals, it is the opposite. For a) P, S, Cl are non - metals and F is the most reactive, so the order is P, S, Cl, F. For b) Be, Mg, Na, Cs are metals and Cs is the most reactive, so the order is Be, Mg, Na, Cs. For c) Cr, Mn, Rb, Fr are metals and Fr is the most reactive, so the order is Cr, Mn, Rb, Fr. For d) B, C, N, O, F are non - metals and the order is B, C, N, O, F.

Answer:

1. a) Li, Ne, Ar; b) Mg, P, S; c) Ge, Sb, I
2. a) K, Cs, Fr; b) N, C, Ba; c) S, Te, Sn
3. a) Be, O, Ne; b) Sr, Ca, F; c) Xe, Ne, He
4. a) Fr; b) Si
5. a) Ba; b) I
6. a) Zr, Al, Zn, Co; b) Ca, Br; c) Ba, Y, Al, Cl; d) I, Br, F
7. a) P, S, Cl, F; b) Be, Mg, Na, Cs; c) Cr, Mn, Rb, Fr; d) B, C, N, O, F