We’re being asked to fill the gap in the fourth row of the table which is to determine the number of electrons.
An element can be represented as:
You can determine the identity of the element using its atomic number:
Atomic number (Z):
• represents the identity of the element
• reveals the number of protons
• in a neutral element:
# of protons = # of electrons
Mass number (A)
• reveals the number of protons and neutrons
mass number = # of protons + # of neutrons
Complete the fourth row of the table.