Question

part 3: solving for neutrons
sometimes the periodic table doesnt give you the number of neutrons directly. use this formula:
molar mass - atomic number (number of protons) = neutrons
practice problems:

1. lithium has an atomic mass of 7 and an atomic number of 3. how many neutrons does it have?

answer:

1. fluorine has 9 protons and an atomic mass of 19. how many neutrons does it have?

answer:

Explanation:

Step1: Apply given formula to Lithium

$\text{Neutrons} = 7 - 3$

Step2: Calculate Lithium's neutron count

$7 - 3 = 4$

Step3: Apply formula to Fluorine

$\text{Neutrons} = 19 - 9$

Step4: Calculate Fluorine's neutron count

$19 - 9 = 10$

Answer:

1. 4
2. 10