Answer:
There are two dots are present on the left side of calcium atom which represents the unpaired electrons present in the outermost shell. This structure is presented by Lewis in order to show the number of unpaired electrons in the atom.
Explanation:
Answer:

Explanation:
Carbon disulphide is the liquid that can be used to separate iron fillings and sulphur powder.
When carbon disulphide is poured into the dish, the sulphur powder gets easily dissolved in the carbon disulfide. The iron fillings are left to settle on the bottom of the dish.
The iron fillings can get seperated through filtration. When the mixture of sulphur powder and carbon disulphide gets completely evaporated, the sulphur powder is left over.
Atomic mass silicon = 28.085 u
1 mol Si ---------------- 28.085 g
? ------------------------ 245 g
245 x 1 / 28.085 => 8.72 mol
answer A