Question

the formula of calcium nitrate, balancing charges of $ca^{2+}$ and $no_{3}^{-}$, is
$ca(no_{3})_{2}$
$cano_{3}$
$ca_{2}no_{3}$
$ca_{2}(no_{3})_{2}$
$ca(no_{3})_{2}$
which is an example of a monatomic ion?
$na^{+}$
$nh_{4}^{+}$
$co_{3}^{2-}$
$no_{3}^{-}$
$so_{4}^{2-}$

Explanation:

First Question (Calcium Nitrate Formula)

Step1: Determine ion charges

Calcium ion: \( \text{Ca}^{2+} \), Nitrate ion: \( \text{NO}_3^- \).

Step2: Balance charges

To balance \( 2+ \) and \( 1- \), we need 2 nitrate ions for 1 calcium ion.
Formula: \( \text{Ca}(\text{NO}_3)_2 \) (note: first option has a typo, last option is correct \( \text{Ca(NO}_3\text{)}_2 \)).

Second Question (Monatomic Ion)

A monatomic ion consists of a single atom. \( \text{Na}^+ \) is from one Na atom. \( \text{NH}_4^+ \), \( \text{CO}_3^{2-} \), \( \text{NO}_3^- \), \( \text{SO}_4^{2-} \) are polyatomic (multiple atoms).

Answer:

s:

1. \( \text{Ca(NO}_3\text{)}_2 \) (the last option: Ca(NO₃)₂)
2. \( \text{Na}^+ \) (the first option: Na⁺)