Download Honors review- ch. 4 Element Symbol Atomic # Atomic mass

Honors review- ch. 4
Element
Symbol
Atomic #
Calcium
Phosphorous
Zinc
Nitrogen
Barium
Aluminum
Potassium
Nitrogen
Ca
P
Zn+2
N-3
Ba+2
Al
K
N
20
15
30
7
56
13
19
7
Atomic
mass
40.078
30.973
65.39
14.000674
137
27
39
14
# Protons
# Neutrons
# Electrons
20
15
30
7
56
13
19
7
20
16
35
7
81
14
20
7
20
15
28
7
54
13
19
7
1. 65.38 is the average of all the different isotopes of zinc. Protons and neutrons
each have a relative mass of 1 amu, so the average mass should not be a fraction
of a number.
2. If two atoms have the same number of protons then they are the same element.
Atoms of the same element with a different mass are called isotopes.
3. If two elements have the same mass, but different protons, they cannot be the same
element. The number of protons identifies the atom.
4. Protons are located in the nucleus, have a relative mass of 1 amu and carry a
positive one charge. Electrons are located outside the nucleus; they have a relative
mass of zero amu and carry a negative one charge. Neutrons are located in the
nucleus; they have a relative mass of 1 amu and have no charge (neutral).
5. The only part of Dalton’s theory that proved to be correct was that atoms combine
id whole number ratios. He thought that atoms were indivisible and indestructible,
but we now know that they can be divided into smaller parts (protons, neutrons
and electrons). They can also be split in a nuclear reaction. He believed that atoms
of the same element were exactly alike. We now know that we have isotopes and
ion- two different forms of the same element.
6. The gold foil experiment was Rutherford’s experiment that changed the model of
the atom. By shooting radiation through gold foil, he saw that most of the
radioactive particles (alpha particles) went straight through. Some alpha particles
were deflected and some were sent backwards… He concluded that the atom was
mostly empty space, that there was a tiny, very dense, positively charged center to
the atom – he called the nucleus.
7. The average atomic mass of neon is 20.179 (check the periodic table- you also
have a worksheet of these equations)
8. Solve for the mass of the second isotope… 12.11 amu
9. The current model of the atom is like the solar system in that they both have a
center, where most of the mass is (sun= nucleus). They have things moving
around the center (planets/ electrons). These “things” both spin (planets on their
axis, electrons spin). Both the solar system and the atom are empty space. They
are different in that the sun is huge compared to the solar system/ planets and the
nucleus is very small. The planets are all different where as electrons are all the
same. The planets follow an orbit; electrons do not have a definite path. The solar
system is mostly 2-dimensional (flat) with the exception of Pluto. The atom is 3D.