Lithium has 1 valence electron available for bonding. So its A.
Because size of an atom INCREASES from top to bottom and DECREASES from left to right on the periodic table. If to elements are in the same period they can't increase in size based on the up or down trend. Instead, notice that Alkali Metals are LEFT of Alkaline Earth Metals. Therefore, the Alkali Metal will be larger than the Alkaline Earth Metals.
Answer: 19.8 l
Explanation:
1) Chemical equation:
2Ca + O₂ → 2CaO
2) Mole ratios: 2 mol Ca : 1 mol O₂ : 2 mol CaO
3) Convert 35.4 g of Ca to moles:
n = mass in grams / molar mass = 35.4 g / 40.1 g/mol = 0.883 mol
4) Volume proportion: 1 mol of gas at STP = 22.4 l
1 mol at STP 0.883 mol at STP
--------------------- = ------------------------------
22.4 l x
⇒ x = 0.883 mol × 22.4 l / 1 mol = 19.8 l ← answer