For sodium, it has 1 valence electron
For oxygen, it has 6 valence electrons
For iron, it has 2 valence electrons
The true about element in period or horizontal row of periodic table is
Each element has one more outer electron than the element before it. (answer B)
<u><em> Explanation</em></u>
In periodic table there are four horizontal rows(periods) that is period 1,2,3 and 4.
Across the period each element has one more electron than element before it.
For example Na and Mg which are in periodic 3.
Na has 2.8.1 or [Ne] 3s¹ electron configuration while Mg has 2.8.2 or [Ne] 3S² electron configuration.
Since Mg has 2 outer electrons while Na has 1 outer electron, Mg has more electron than Na.
Answer:
I am not sure but I will say 5625
Explanation:
