लैंथेनाइड्स कुल कितने रासायनिक तत्वों की एक श्रृंखला है?

The correct order of increasing metallic character of Na, Be, P, Mg and Si is:

Which of the following is the correct order of increasing atomic radii for nitrogen, oxygen, and fluorine?

Which of the following represents the correct increasing order of atomic radii for the elements fluorine (F), oxygen (O), and nitrogen (N)?