Question

question 18 the formula for calcium nitrate is blank 1. blank 1 add your answer question 19 the formula for magnesium phosphide is blank 1 blank 1 add your answer

Explanation:

Question 18

Step1: Determine ion charges

Calcium ion is $Ca^{2+}$ (group 2 metal, +2 charge), nitrate ion is $NO_3^-$ (polyatomic ion, -1 charge).

Step2: Balance charges

To balance +2 and -1, we need 2 nitrate ions for 1 calcium ion. Using criss - cross method: $Ca^{2+}$ and $NO_3^-$, so formula is $Ca(NO_3)_2$.

Step1: Determine ion charges

Magnesium ion is $Mg^{2+}$ (group 2 metal, +2 charge), phosphide ion is $P^{3 -}$ (non - metal, -3 charge).

Step2: Balance charges

Find the least common multiple of 2 and 3, which is 6. So we need 3 $Mg^{2+}$ ions (3×2 = +6) and 2 $P^{3 -}$ ions (2×(- 3)= - 6). Using criss - cross method, the formula is $Mg_3P_2$.

Answer:

$Ca(NO_3)_2$

Question 19