Answer:
nitrogen, phosphorus, potassium, and calcium
Explanation:
Just put it.
It's <span>Argon
about 1% in the atmosphere</span>
Its a compound hope this helped u<span />
Answer:
Seven.
Explanation:
A period is a horizontal row of the periodic table. There are seven periods in the periodic table, with each one beginning at the far left. A new period begins when a new principal energy level begins filling with electrons.
