Answer:
Nickel has 2 electrons in its valence level.
Explanation:
The Electronic Configuration of the elements is the arrangement of all electrons of an element in energy levels and sub-levels (orbitals).
There are 7 energy levels, numbered from 1 to 7. Each level is divided into sub-levels. These sub-levels into which each level is divided can be up to 4. These 4 sub-levels are called: s, p, d, f.
According to the periodic table entry, you can see that the nickel has an electronic configuration of [Ar] 3d⁸ 4s²
The number that precedes the representative letter of each orbital or sub-level indicates the level of energy where the electron is located, the letter indicates the type of orbital or sub-level where the electron is located and the exponent indicates the number of electrons found in the orbital.
Note that Ar is the noble gas of the previous period. In square brackets, as shown in the case of nickel, indicates the internal electronic structure of the element. So the electronic configuration of the nickel is:
1s² 2s² 2 p⁶ 3s² 3p⁶ 3d⁸ 4s²
Valencia electrons are the electrons found in the last electronic layer (called valence orbitals). The last electronic layer is the layer furthest from the nucleus, which in this case can be seen to be the electronic layer or level 4. At this level you can see the letter s, which, as mentioned, indicates the type of orbital where the electrons are located, and the exponent 2, which indicates the number of electrons found in said orbital.
So, <u><em>nickel has 2 electrons in its valence level.</em></u>
<u><em></em></u>
