Chapter 15, Problem 10RQ

To determine

The change in properties of an element across any period of the periodic table.

Answer to Problem 10RQ

Across any period the properties of elements gradually change and this gradual change is called a periodic trend.

Explanation of Solution

There are total seven rows in the modern periodic table. The elements will same number of electron shells fall under same periods. From left to right through the periods, elements with more number of electrons in the outer shells are added. Thus from left to right, the elements become less metallic.

Across any period, the properties of elements gradually change. This gradual change is called a periodic trend. This trend repeats from one horizontal row to the next. Each horizontal row is called a period because it corresponds to one full cycle of a trend.

Conclusion:

Therefore, across any period the properties of elements gradually change and this gradual change is called a periodic trend.