Count protons, neutrons and electrons in atoms, ions and isotopes
Grade 10 Science Worksheet
Circle the best answer, or write your answer on the line.
A calcium ion has 20 protons and a 2+ charge. How many electrons does it have, Ari?
An aluminum ion has 13 protons and a 3+ charge. How many electrons does it have, Esme?
Read this first
Atom diagram of a fluoride ion
9 protons and 10 neutrons in the nucleus, and 10 electrons in shells of 2 and 8. Notation: mass number 19 over atomic number 9, then F with a 1− charge.
In the diagram, why is the fluoride ion's charge 1−, Jun?
- It has one more neutron than protons
- It has one more electron than protons
- It lost a proton
In the diagram, how many neutrons does the fluoride ion have, Kira?
- 9
- 19
- 10
In the diagram, why is this still fluorine, Luz?
- It still has 9 protons
- It has 10 electrons in it
- It gained a proton
A sodium atom loses one electron. What does it become, Milo?
- A new element
- A 1− ion
- A 1+ ion
An oxygen atom gains two electrons. What is its charge, Noah?
- 2−
- No charge
- 2+
When an atom becomes an ion, which particles change in number, Pia?
- Protons
- Electrons
- Neutrons
How do carbon-12 and carbon-14 differ, Ren?
- Carbon-14 has 2 more protons
- Carbon-14 has 2 more neutrons
- Carbon-14 has 2 more electrons
What do isotopes of one element share, Tala?
- The same atomic number
- The same mass number
- The same number of neutrons