It cropped out “D” but D is Calcium please help asap !!!

Option A. Potassium.

Explanation:

The electronic configuration of the element given above is:

1s2 2s2 2p6 3s2 3p6 4s1

To know which element has the above electronic configuration, we simply calculate the atomic number of the element. This can be obtained by adding the electrons in the electronic configuration as follow:

2 + 2 + 6 + 2 + 6 + 1 = 19

The atomic number of the element is 19.

Atomic number is the identity of elements in the periodic table. No two elements have the same atomic number.

Therefore, the element is Potassium because only potassium has atomic number of 19 in the periodic table.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.