Answer:
In an atom, the first energy level can hold <u><em>2</em></u> electrons. The second energy level can hold <em><u>8</u></em> electrons. The third energy level can hold <u><em>18 </em></u>electrons.
Explanation:
There are 7 energy levels, numbered from 1 to 7, and in which electrons are distributed. Each level is divided into sub-levels. These sub-levels into which each level is divided can be up to 4 and these are called: s, p, d, f. In the sub-level s there can only be a maximum of 2 electrons, in p there can be a maximum of 6 electrons, in the sub-level d 10 electrons and finally in the sub-level f there can be a maximum of 14 electrons.
In level 1 there is only one sub-level, which will be the s. In level 2 there are 2 sub-levels, the s and the p. At level 3 there are 3 sub-levels s, p and d. And at level 4 there are 4 sub-levels, the s, the p, the d and the f.
As in level 1 there is only the sub-level s, and this sub-level can only contain 2 electrons at most, then <u><em>the first energy level can hold 2 electrons.</em></u>
As in level 2 there is the sub-level s and p, and these sub-levels can only contain 2 and 6 electrons at most respectively, by adding them you get that <u><em>the second energy level can hold 8 electrons.</em></u>
As in level 3 there is the sub-level s, p and d, and these sub-levels can only contain 2, 6 and 10 electrons at most respectively, by adding them you get that <u><em>the third energy level can hold 18 electrons.</em></u>
The maximum number of electrons in each level can also be calculated by means of the expression: 2*n², where n is the level to which the electrons belong. Then:
- First Level: 2*1²= 2 electrons
- Second Level: 2*2²= 8 electrons
- Third Level: 2*3²= 18 electrons
You can see that you get the same amount of electrons, so either of the two ways of thinking is correct.
