Determine the identity of the element that contains exactly three 4p electrons in the ground state

Arsenic (As)

Explanation:

The electron configuration of arsenic is; 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p3 or [Ar]4s2 3d10 4p3 for short.

Arsenic is a group 15 element. All group 15 elements have outermost electron configuration of ns^2 np^3. Arsenic is the only member of the group that possesses exactly three electrons in the 4p orbital.

Hence As is the element we need to identity in the question.

the answer

explanation:

the capillary tube was too close to the bottom of the beaker.

the ruler may have moved.

water got into the capillary tube.

the temperature was not allowed to equilibrate in the 2-4 minutes.