Question

Which is the largest atom in period 3 ? How many electrons does it have in its outermost shell.​

Answer 1

Answer:1) sodium 2) Number of electrons in outermost shell = 1

Explanation:

1) Here sodium is a metal and we know that metals have the tendency to loss electrons.Metals will have bigger atomic radius because of there weaker nuclear charge.So the outermost shell will be furthest in metals.We also know that in a period in left side there will be metals and as we slowly move to the right we will find the are no metals.
                                         In period 3 the left most metal is sodium,which thus have the weakest nuclear charge among all other elements in period 3,so it will have the biggest atomic radius.

2)The electronic configuration for Sodium is as follows
  *2 8 1
here the outermost shell has only 1 electron.So answer 1

Answer 2

Hope it helps ^_^

Answer:

Argon (2, 8, 8)

Explanation:

Because elements of the same period have the same number of electron shells, then Argon is technically the largest atom of Period 3 because it has 18 electrons which is the highest in this period.