Choose the coefficient for blank 1 (in front of Rb) ___ Rb + ___ P --> ___ Rb3P

options:

3

1

4

2

3

Explanation:

Step 1: RxN

Rb + P → Rb₃P

Step 2: Balance RxN

We will need 3 Rb's on both sides.

3Rb + P → Rb₃P

first one is the correct answer

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.