The element with 5 electrons in its 3d sublevel is...?

manganese, Mn

Explanation:

From the question, we have;

The number of electrons in the 3d sub level = 5

The kind of element = d-block element

On the periodic table, the elements with electrons in the 3d-sublevel in increasing order are;

Sc, 3d¹ 4s²

Ti  3d² 4s²

V  3d³ 4s²

Cr 3d⁵ 4s¹

Mn 3d⁵ 4s²

Fe 3d⁶ 4s²

Co 3d⁷ 4s²

Ni 3d⁸ 4s²

Cu 3d¹⁰ 4s¹

Zn 3d¹⁰ 4s²

The elements with 5 electrons in their 3d-sublevel are chromium Cr and manganese, Mn however the electronic configuration of chromium is given as 3d⁵ 4s¹ rather than 3d⁴ 4s² due to the minor difference in the gap of energy between the 3d and the 4s orbital as such the element that has the main characteristic of 5 electrons in its 3d sub level is manganese, Mn.

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72

im pretty sure its b