Masses of Atoms
OBJECTIVE: Students will learn about the masses of atoms
1) What charge does
the Nucleus have?
2) What two
particles are found
in the Nucleus?
1. Identify the mass number and atomic number of a
chlorine atom that has 17 protons and 18 neutrons.
17+18 = 35 Mass # (protons + neutrons)
Atomic # = 17 (equal to the # of protons)
2. If a hydrogen atom has 2 neutrons and 1 proton, what
is its mass number? Protons + neutrons = Mass #
2+1=3
3. How are the isotopes of an element different?
Isotopes have a different number of neutrons and mass
4. Carbon-12 and Carbon-14 are isotopes. Carbon's
atomic number is 6. How many neutrons are in Carbon12 and Carbon-14?
Mass = 12 and 14, protons = 6
therefore, 12-6 = 6 and 14-6 = 8
5. What is the atomic mass of an atom that has
3 protons, 4 neutrons, and 3 electrons?
Mass = protons + Neutrons
7 = 4 + 3
6. Find the number of neutrons in Oxygen if it has
8 protons and a mass number of 16.
7. Xenon has 77 neutrons and 54 protons, what is
its atomic mass?
video: how small is an atom?
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