Chapter U1.19, Problem 14E

Interpretation Introduction

Interpretation:

The periodic pattern for the charges of ions must be explained.

Concept introduction:

The periodic patterns are trends of elements which are arranged in the periodic table in order of increasing atomic number. These trends include, size of the atom, ionization energy, electronegativity etc.

Explanation of Solution

On moving from left to right in a period, due to increase in the number of valence electrons, the positive charge inceases from +1 to +3. This is because atoms can lose their valence electrons. These are metals from group 1 to 3. After +3, element cannot have +4 charge thus, atoms of element starts sharing electrons. The atoms with valence electrons more than +4 can accept electrons to form negative charged ions.

In this case, the charge on ion decreses from -3 to -1. These are non-metals from group 15 to 17. Thus, across a period positive charge increses up to + 3 and negative charge decreses from -3 to -1. Group 18 elements are noble gases they do not react to from any ion.

Now, on moving from top to bottom in a group the charge on the elements remain the same because all the elements in same group have same number of valence electrons.

Conclusion

On moving top to bottom, charge on ion remains the same and on moving from left to right positive charge increases and negative charge decreases.