atomic structure

what she’ll is filled first and how many electrons can it hold?

the innermost shell is filled first and it can hold a maximum of 2 electrons

how many electrons can the second and third shell hold?

eight electrons each

how many electrons does a lithium atom hold?

3, two on the inner shell and one on the second shell

how many electrons can a calcium atom hold?

20

what do atoms of the same element have in common?

they have the same number of protons

if an atom has an equal number of protons and electrons what does this mean?

it means they won’t have an overall electrical charge

what is the mass number of an atom?

the number of protons and neutrons in its nucleus

what do different elements usually have?

a different mass number but can have the same

how can the symbol for an atom be written?

with the mass number at the top and the proton number at the bottom

how could you calculate the number of subatomic particles in an atom?

add the proton and mass numbers together

what does the number of protons and number of electrons equal?

the atomic number

what does the number of neutrons equal?

mass number - proton number