आधुनिक आवर्त सारणी में ऊर्ध्वाधर पंक्तियाँ (Vertical columns) क्या कहलाती हैं?

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)?