Chapter 8, Problem 8.74QP

(a)

Interpretation Introduction

Interpretation:

A halogen element in the fourth period has to be given with reference to the periodic table.

Concept Introduction:

Modern periodic table contains groups and periods where the elements same number of outer electrons comes under same group and elements having same number of electron shells are in same period.

Group 7A in the periodic table contains 7 valence electrons and the outer electronic configuration of halogens is ${\text{ns}}^{\text{2}}{\text{np}}^5$. Fluorine, chlorine, bromine, iodine and astatine are the halogens.

(b)

Interpretation Introduction

Interpretation:

An element having similar chemical properties to phosphorus has to be given with reference to the periodic table.

Concept Introduction:

Modern periodic table contains groups and periods where the elements same number of outer electrons comes under same group and elements having same number of electron shells are in same period.

Elements with same valence electrons are placed in the same group in periodic table

Chemical properties of an element can be determined by the number of electrons in the subshell containing the outermost electrons.

The elements with same number of valence electrons have similar physical and chemical properties.

(c)

Interpretation Introduction

Interpretation:

The most reactive metal in 5^th period has to be given with reference to the periodic table.

Concept Introduction:

Modern periodic table contains groups and periods where the elements same number of outer electrons comes under same group and elements having same number of electron shells are in same period.

Along the period, the valence electron is added to the same shell and thus attraction by the nucleus gets stronger. Hence, ionization energy increases and reactivity decreases from left to right.

(d)

Interpretation Introduction

Interpretation:

The element similar to strontium with an atomic number less than 20 has to be given with reference to the periodic table.

Concept Introduction:

Diagonal relationship is the trend observed in the chemical behavior of a certain pairs of elements that are diagonally adjacent in different periods and groups in the periodic table.