Chapter U1.10, Problem 2E

Interpretation Introduction

Interpretation:

The variation of two properties of atoms across the period needs to be explained.

Concept introduction:

Element can be defined as the basic unit of any substance. It is composed of same type of atoms. All known elements are placed in the long form of periodic table.

In this table, all elements are placed according to their atomic number. Here atomic number indicates the number of protons in the atom of an element.

Answer to Problem 2E

The ionization energy increases across the period with decrease in the atomic size.

Explanation of Solution

There are several properties which show trends in the periodic table. Some common properties are atomic size, electron affinity, electronegativity and ionization energy.

Across the period, the atomic size decreases because the nuclear attraction increases whereas the number of valence shell remain the same.

Therefore, the atomic size decreases across the period. As the atomic size decreases, the ionization energy increases as more energy is required to remove an electron from the valence shell. Thus, the ionization energy increases across the period with decrease in the atomic size.

Conclusion

The ionization energy increases across the period with decrease in the atomic size.