Question

2. What are per
iods and groups. tell this question answer​

Answer 1

Period: A period in the periodic table is a row of chemical elements. All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor.

Group: a group (also known as a family) is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table; the f-block columns (between groups 3 and 4) are not numbered. ... Groups may also be identified using their topmost element, or have a specific name.