Chapter 12, Problem 90A

(a)

Interpretation Introduction

Interpretation: The larger atom from the pair of sodium and calcium is to be identified.

Concept Introduction: In the periodic table, the atomic size of elements varies in a consistent pattern. In general, the size of an atom decreases as one moves from left to right across a period and increases as one moves from top to bottom across a group.

Answer to Problem 90A

The sodium atom is larger than calcium.

Explanation of Solution

In the periodic table, sodium is placed in the first period. In the periodic table, calcium is placed in the seventeenth period of the elemental system. The atomic size decreases when moving from left to right. Therefore, the largest atom is sodium.

(b)

Interpretation Introduction

Interpretation: The larger atom from the pair of arsenic and nitrogen is to be identified.

Concept Introduction: In the periodic table, the atomic size of elements varies in a consistent pattern. In general, the size of an atom decreases as one moves from left to right across a period and increases as one moves from top to bottom across a group.

Answer to Problem 90A

The arsenic atom is larger than nitrogen.

Explanation of Solution

Arsenic is an element belonging to the fourth group of the periodic table. Nitrogen is an element belonging to the first group of the periodic table. Moving down a group in the periodic table, the size of the atom increases. Therefore, the largest atom is arsenic.

(c)

Interpretation Introduction

Interpretation: The larger atom from the pair of fluorine and cesium is to be identified.

Concept Introduction: In the periodic table, the atomic size of elements varies in a consistent pattern. In general, the size of an atom decreases as one moves from left to right across a period and increases as one moves from top to bottom across a group.

Answer to Problem 90A

The cesium atom is larger than fluorine.

Explanation of Solution

The second group of the periodic table has fluorine as an element. Cesium is an element belonging to the sixth group of the periodic table. Moving down a group in the periodic table, the size of the atom increases. Therefore, the largest atom is cesium.