Make a quick chart with each element represented, and count them up. HINT - leave the polyatomic anions together - in this case, PO4
Left Right 1 Ca 3 2 O 1 5 H 2 1 PO4 2
Begin by balancing like finding common denominators of fractions - apply to both sides: I started by adding a 2 in front of H3PO4 on the left, them 6 in front of H2O on the right. Last, a 3 in front of Ca (OH)2. Then, re-count using the chart format to make sure you're right.
Electronegativity is a measure of an atom's ability to attract shared electrons to itself. On the periodic table, electronegativity generally increases as you move from left to right across a period and decreases as you move down a group.
