Questions: Atomic Number: What Makes an Element Unique
3 questions to test your understanding
Score: 0 / 3
Question 1 Multiple Choice
An atom has 8 protons. What element is it?
ACarbon
BNitrogen
COxygen
DFluorine
Oxygen has an atomic number of 8, meaning every oxygen atom contains exactly 8 protons. Carbon has 6, nitrogen has 7, and fluorine has 9. The number of protons is the defining feature of an element.
Question 2 True / False
Two atoms with different numbers of protons can be the same element.
TTrue
FFalse
Answer: False
The number of protons defines which element an atom is. If two atoms have different proton counts, they are by definition different elements. Atoms of the same element can differ in neutron count (isotopes), but never in proton count.
Question 3 Short Answer
A neutral atom has an atomic number of 11. How many electrons does it have?
Think about your answer, then reveal below.
Model answer: 11 electrons.
The atomic number tells you the number of protons. In a neutral atom, the number of electrons equals the number of protons so the charges balance. An atomic number of 11 means 11 protons and therefore 11 electrons. This element is sodium.