Ch 4 atoms and isotopes
1. The three subatomic particles are ________________, _______________ and ______________
2. Neutrons are neutral. Electrons have a ______________________charge so are abbreviated, e-.
Protons have a __________________ charge so are abbreviated, p+.
3. The mass of a proton is equal to the mass of a (n) ________________________. Both these
subatomic particles have a mass of 1 amu. The subatomic particle, __________________, have
so little mass we say their relative mass is zero. The only subatomic particle not in the nucleus is
4. Section 4.3 the atomic mass is always equal to the number of __________________. The
number of protons in an element, give the element its identity. For example, hydrogen always
has 1 proton, lithium has ______________p, and nitrogen has ___________ p.
5. The mass number of an atom is equal to the sum of the number of _________________ and the
number of _____________________. Since helium has 2 n and 2p, its mass would be 4amu. If
an element has 4n and 5p, its atomic mass would be ________________. Since this atom has 5p
the name of this element would be ______________________.
6. To find the number of neutrons, find the difference between the mass number and the atomic
number (or protons). In neutral atoms the number of protons = the number or ____________
7. Using the lithium example, finish the chart below. Assume atoms are neutral.
Notice in the table above, the element lithium appears twice. The atomic number is the same
but the number of _________ and therefore the mass is different in isotopes. There are two
ways to indicate isotopes.
Type 1: name-mass number
ex: 7 Li
On the back: page 119 # 25,28,30,32
ex: carbon -12