Atomic mass and numbers Flashcards
(5 cards)
1
Q
What is the relative atomic mass (Ar) formula?
A
Ar = (mass1 × %abundance1 + mass2 × %abundance2) / 100
2
Q
Why is chlorine’s Ar 35.5?
A
Because it’s a weighted average: (35×75 + 37×25)/100 = 35.5
3
Q
What is the atomic number?
A
Number of protons in the nucleus.
4
Q
What is the mass number?
A
Number of protons + neutrons in the nucleus.
5
Q
What is an isotope?
A
Atoms of the same element with different numbers of neutrons.
