Isotopes
How many protons are in all chlorine (Cl) atoms?
17
A student says "I think that some chlorine atoms have 16 protons." Explain why this student is not correct.
Because chlorine is number 17 on the periodic table.
Why is this number called a "mass" number?
It is the mass of the atom
Do all isotopes of an element have the same mass number?
No, Hydrogen 1 and Hydrogen 2 have a different mass number.
Can two atoms with the same mass number ever be isotopes of each other?
No, isotopes have different mass numbers.
How is the mass number determined?
Protons and neutrons added
Where is the atomic number located in the isotope symbol?
The bottom number
In a neutral atom, how does the number of electrons compare to the number of protons?
They both have the same amount
Do all isotopes of an element have the same atomic number?
Yes, the atomic number doesn't change. Hydrogen 1 and Hydrogen 2 only have 1 proton
What does the atomic number represent?
number of protons
Discuss why this relationship is important in making a "neutral" atom.
they cancel each other out
What corner of the isotope symbol contains the mass number?
top left
