Download Atomic Structure and Theory Test Review

Name ____________________________P.__ Date___________
Atomic Structure and Theory Test Review (TEST IS ON ___________)
Atomic Theory History
1) democritus is credited with naming the atom, which he
said is the building block of all matter & means
indivisible
2) Dalton believed the atoms were solid balls and that
atoms of one element are different from the atoms of
another element, but he didn’t know how they were
different.
3) Using a cathode ray tube, Thomson identified the
electron as a negative particle. He knew electrons
were in atoms, so he came up with the plum pudding
model. He thought the negative electrons were
floating throughout a positive substance.
Answer Bank for
fill in atom anat.
0 amu
1 amu
14
15
16
17
18
21
21
22
24
27
Atomic number
Average
Decimal
Different
Identity
Isotope
Isotopes
Mass
Mass number
Mass numbers
Negative
Neutral
Positive
Strong nuclear
Sulfur
Answer Bank for fill
in atomic theory
Solid
Small
Rutherford
Positive
Positive
Plum pudding
Planetary
Nucleus
Mass
Indivisible
Empty
Electrons
Electron cloud model
Electron
Different
Democritus
Cathode
4) Through his gold foil experiment,
rutherford identified that the
nucleus of an atom is positiveand that the atom is
mostly empty space. Although the nucleus is just a
small part of the atom, he found that the mass of the
atom is in the nucleus. He came up with the planetary
model, but he didn’t know that protons and neutrons
were in the nucleus.
5) Bohr believed the electrons orbited the nucleus and
that the nucleus contained neutrons and protons. The
negative electrons are attracted to the positively
charged nucleus.
6) The current model is the electron cloud in which the
protons and neutrons are in the nucleus and the
electrons are found in cloud-like regions surrounding
the nucleus.
Atom Anatomy
7) The nucleus of the atom holds the protons and
neutrons. The nucleus is held together by the strong
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nuclear force. Electrons are attracted to the positive nucleus and are found
orbiting the nucleus.
8) Protons have a positive charge and a mass of 1 amu Neutrons have a
neutral charge and a mass of 1 amu. Electrons have a negative charge and
a mass of0 amu
9) The number of protons is the atom’s number . The number of protons also
gives the atom itsidentity Change the number of protons, you will get a
different type of atom.
10)
The element sulfur has an atomic number of 16, so it has 16 protons.
11)
The mass number of an atom is equal to its number of protons and
neutrons, since both of these particles have a mass of 1 amu. If you alter the
number of neutrons an atom has, you will alter its mass number.
12)
An isotope is an atom of the same element but has a different mass
number because it has more or less neutrons.
13)
Scandium- 45 and Scandium- 48 are isotopes The 45 and 48
represent the mass #s of the two isotopes. Scandium-45 has 21 protons and
24 neutrons, whereas Scandium-48 has 21 protons and 27 neutrons.
14)
Argon’s atomic number is 18 and its mass number is 40. Argon has 18
protons and 22 neutrons.
15)
The atomic mass is different from the mass number because the
atomic mass is an average of the masses of many atoms of the same
element. This is why the atomic mass is a decimal but mass number is
always a whole number.
16)
Atom A, B and C are all atoms of the same element X. Atom A has 7
protons and 7 neutrons. Atom B has 7 protons and 8 neutrons. Atom C has
7 protons and 10 neutrons.
a) The mass number for atom A is 14
b) The mass number for atom B is 15
c) The mass number for Atom C is 17
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d) The average atomic mass for element X is 15.3 amu. (not in answer
bank)
e)
119
Sn - The atomic number of Sn is 50 and the mass number is
50
119 Sn has 50 protons and 69 neutrons. (not in answer bank)
17)
Write a symbol which represents an isotope of Sn that has 67
neutrons. 11750Sn (not in answer bank)
Ions
18)
Atoms have the same number of protons and
electrons which makes them electrically neutral
19)
But, since electrons are found outside the nucleus, it
is easy for an atom to lose or gain electrons, and when
this happens, an atom becomes an ion
20)
So if an atom of Flourine gains an electron it will
become an ion of Flourine. It is still fluorine but it now has
a negative charge.
Answer Bank for
fill in nuclear
Many
Unstable
Radioactive
Particles
Alpha
Weakest
Gamma
Helium
Electron
Energy
Neutrons
Neutrons
Leaves
One
No effect
Fission
Fusion
Chemical
Half
1
1.5
2
4
84
Answer
Bank for fill
in ions
Positively
Never
Neutral
Lose
Ion
Gain
Flourine
Electrons
Electrons
21)
Atoms that gain electrons
become negatively charged and atoms the lose
electrons become positively charged.
22)
An atom with a -3 charge gained 3 electrons
and atom with a +2 charge lost 2electrons
23)
Remember, atoms become ions by losing or
gaining electrons. The number of protons is never
altered to make ions.
Nuclear Chemistry
24)
Smaller atoms have stable nuclei when their
neutron to proton ratio is 1:1.
25)
Medium sized atoms have stable nuclei when
their neutron to proton ratio is1.5: 1.
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26)
Atoms of atomic number 84 or more all have unstable nuclei because
they just have too many protons and neutrons.
27)
Atoms with too many or too few neutrons will also have unstable
nuclei. These atoms are called radioactive
28)
Unstable nuclei will lose energy and particles in order to make their
nuclei stable.
29)
Using the Band of Stability graph, is
119
Sn stable or unstable? Stable
50
(not in answer bank)
30)
3 types of particles are released by radioactive nuclei – alpha, beta,
and gamma.
31)
Alpha radiation is the weakest and can be blocked by paper. Gamma
radiation is the strongest and can penetrate body tissues.
32)
An alpha particle is the nucleus of a helium atom. The beta particle is a
high energy electron The gamma particle is a packet of energy called a
photon.
33)
When an atom loses an alpha particle, it loses 2 protons and
2neutrons The atom’s atomic number decreases by 2 and its mass number
decreases by 4
34)
When atom goes through beta decay, one of its neutrons breaks down
into a proton and an electron. The electron leave the nucleus, but the proton
stays behind. This extra proton causes the atomic number to increase by1
but has no effect on the mass number.
Be able to balance the nuclear equations like you did on the worksheets.
35)
In a fission reaction, an atom’s nucleus is broken down.
36)
In a fusion reaction, two nuclei are fused (put together) to make a
larger nucleus.
37)
Both fusion and fission reactions release a lot of energy, much more
than any chemical reaction can release.
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38)
Half-life is how long it takes for half of the substance to decay into
another substance in a nuclear reaction.
39)
If a 200 g sample of an isotope has a half-life of 30 years. In 90 years
there will be 25 g of it left. (not in answer bank)
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