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, cl, br, f
d) i, f, br, sn

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.

a)

Li (lithium) has an atomic mass of approximately 6.94, Ne (neon) has an atomic mass of approximately 20.18, and Ar (argon) has an atomic mass of approximately 39.95. So the order is Li, Ne, Ar.

b)

Mg (magnesium) has an atomic mass of approximately 24.31, P (phosphorus) has an atomic mass of approximately 30.97, and S (sulfur) has an atomic mass of approximately 32.07. So the order is Mg, P, S.

c)

Ge (germanium) has an atomic mass of approximately 72.63, Sb (antimony) has an atomic mass of approximately 121.76, and I (iodine) has an atomic mass of approximately 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.

a)

K (potassium), Cs (cesium), and Fr (francium) are in the same group (Group 1). As we move down the group, the atomic radius increases. So the order is K, Cs, Fr.

b)

C (carbon) and N (nitrogen) are in the second - period, and Ba (barium) is in the sixth - period. Ba has the largest atomic radius. Among C and N, C has a larger atomic radius than N. So the order is N, C, Ba.

c)

S (sulfur) is in the third - period, Te (tellurium) is in the fifth - period, and Sn (tin) is in the fifth - period. Sn has a larger atomic radius than Te. So the order is S, Te, Sn.

Step3: Recall ionization - energy trends

Ionization energy increases across a period and decreases down a group.

a)

Be (beryllium), O (oxygen), and Ne (neon) are in the second - period. Be has the lowest ionization energy, followed by O, and Ne has the highest. So the order is Be, O, Ne.

b)

Ca (calcium) and Sr (strontium) are in Group 2, and F (fluorine) is in Group 17. Sr has a lower ionization energy than Ca, and F has the highest. So the order is Sr, Ca, F.

c)

He (helium), Ne (neon), and Xe (xenon) are in Group 18. Xe has the lowest ionization energy, followed by Ne, and He has the highest. So the order is Xe, Ne, He.

Step4: Identify element with largest atomic mass

a)

Li has an atomic mass of approximately 6.94, Na has an atomic mass of approximately 22.99, and Fr has an atomic mass of approximately 223. So Fr has the largest atomic mass.

b)

Na has an atomic mass of approximately 22.99, Al has an atomic mass of approximately 26.98, and Si has an atomic mass of approximately 28.09. So Si has the largest atomic mass.

Step5: Identify element with largest atomic radius

a)

Be, Sr, and Ba are in Group 2. Ba has the largest atomic radius as it is the lowest in the group.

b)

F, Cl, and I are in Group 17. I has the largest atomic radius as it is the lowest in the group.

Step6: Recall electronegativity trends

Electronegativity increases across a period and decreases down a group.

a)

Zr, Zn, Al, and Co: Zr has the lowest electronegativity, followed by Zn, then Co, and Al has the highest. So the order is Zr, Zn, Co, Al.

b)

Ca, Cl, Br, and F: Ca has the lowest electronegativity, followed by Br, then Cl, and F has the highest. So the order is Ca, Br, Cl, F.

c)

Ba, Y, Al, and Cl: Ba has the lowest electronegativity, followed by Y, then Al, and Cl has the highest. So the order is Ba, Y, Al, Cl.

d)

Sn, I, Br, and F: Sn has the lowest electronegativity, followed by I, then Br, and F has the highest. So the order is Sn, I, Br, F.

Step7: Recall reactivity trends

For non - metals, reactivity increases across a period and decreases down a group. For metals, reactivity increases down a group and decreases across a period.

a)

P, S, Cl, and F: P has the lowest reactivity, followed by S, then Cl, and F has the highest. So the order is P, S, Cl, F.

b)

Be, Mg, Na, and Cs: Be has the lowest reactivity, followed by Mg, then Na, and Cs has the highest. So the order is Be, Mg, Na, Cs.

c)

Cr, Mn, Rb, and Fr: Cr has the lowest reactivity, followed by Mn, then Rb, and Fr has the highest. So the order is Cr, Mn, Rb, Fr.

d)

B, C, N, O, and F: B has the lowest reactivity, followed by C, then N, then O, and F has the highest. So 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, Zn, Co, Al
b) Ca, Br, Cl, F
c) Ba, Y, Al, Cl
d) Sn, 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