Question

worksheet: atomic structure
use your notes from the atomic structure program to answer the following questions.

1. the atomic number tells the number of positively charged ____ in the nucleus of an atom. the atom is __ because this is also the number of __ charged ____ in the atom.
2. the mass number tells the total number of ____ and __ in the nucleus of an atom. these particles collectively are called ____ since both are located in the nucleus.
3. isotopes are atoms of the same element with different numbers of ____ which results in different ____ numbers.
4. write the hyphen notation of the three isotopes of hydrogen:

a. hydrogen - 1
b. 1h
c.

1. fill in the following chart (hint: isotopes may have different masses than the periodic table lists!):

symbol atomic # mass # # of protons # of electrons # of neutrons
hg 80 201 80 80 121
mo 42 96 42 42 54
cu 29 64 29 29 35
c 6 14 6 6 8
p 15 31 15 15 16
pb 82 208 82 82 126
na 11 23 11 11 13

Explanation:

1. The atomic number represents protons. Atoms are neutral as proton number equals electron number (negatively charged).
2. Mass number is sum of protons and neutrons. Protons and neutrons are nucleons.
3. Isotopes of same element have different neutron numbers, leading to different mass numbers.
4. Hyphen notation for hydrogen isotopes: a. Hydrogen - 1 (protium), b. Hydrogen - 2 (deuterium), c. Hydrogen - 3 (tritium).
5. For the chart:

• Hg: Atomic # = 80 (protons = 80, electrons = 80 as neutral), neutrons = mass # - atomic # = 201 - 80 = 121.
• Mo: Atomic # = 42 (protons = 42, electrons = 42), neutrons = 96 - 42 = 54.
• Cu: Symbol for element with atomic # 29. Mass # = protons + neutrons = 29 + 35 = 64.
• C: Atomic # for carbon is 6 (protons = 6, electrons = 6), neutrons = 14 - 6 = 8.
• P: Symbol for element with atomic # 15 (protons = 15, electrons = 15), neutrons = 31 - 15 = 16.
• Pb: Atomic # for lead is 82 (protons = 82, electrons = 82), neutrons = 208 - 82 = 126.
• Na: Mass # = protons + neutrons = 11 + 13 = 24.

Answer:

1. protons; neutral; negatively; electrons
2. protons; neutrons; nucleons
3. neutrons; mass
4. a. Hydrogen - 1, b. Hydrogen - 2, c. Hydrogen - 3

5.

Symbol	Atomic #	Mass #	# of protons	# of electrons	# of neutrons
Mo	42	96	42	42	54
Cu	29	64	29	29	35
C	6	14	6	6	8
P	15	31	15	15	16
Pb	82	208	82	82	126
Na	11	23	11	11	13