Name two elements which exists as a single atom.

Q. Name two elements having a single electron in their outermost shell.

Q. Which among the group-$15$ elements does not exists as tetra atomic molecule?

Q. (a) Name three elements that have a single electron in their outermost shells.
(b) Name two elements that have two electrons in their outermost shells.
(c) Name three elements with completely filled outermost shells.

Q. Atoms of most elements are not able to exist independently’. Atoms which exist as independent atoms among the following is/are:

Q. Question 47(a)
Mendeleev predicted the existence of certain elements not known at that time and named two of them as Eka-Silicon and Eka-Aluminium.

Name the elements which have taken the place of these elements.