the number of protons in an atom is known as its atomic number. atoms that share the same atomic number are…
the number of protons in an atom is known as its atomic number. atoms that share the same atomic number are classified as the same chemical element. below is a model representing an atom of the chemical element helium. what is heliums atomic number? which of the following models also represents a helium atom?
Answer
Explanation:
Step1: Count protons in helium model
The given helium - atom model has 2 protons. Since atomic number is the number of protons, helium's atomic number is 2.
Step2: Identify correct helium model
A helium atom has 2 protons. The first model among the options has 3 protons, the second has 1 proton, and the third has 2 protons. So the third model represents a helium atom.
Answer:
2 Third model (the one with 2 protons)