Atomic Models
Which model shows the atom as a solid sphere, with no subatomic particles?
Dalton's model/billiard ball model/solid sphere model
Which particles are found in the nucleus?
Protons and neutrons
The columns of the periodic table are called _________, and the rows are called __________.
groups, periods
Oxygen has an atomic number of 8. How many electrons will a neutral atom of oxygen have?
8
How are different isotopes of the same element similar and different from each other?
Same number of protons, different number of neutrons
Which atomic model is the most modern and based on quantum mechanics?
The electron cloud model
True or False: atoms are solid
False: atoms are mostly empty space
Which element is in group 2, period 3?
magnesium
Determine the number of neutrons in an atom of carbon-13
13 - 6 = 7
Carbon-14 is commonly used to date organic remains less than 5000 years old. How many neutrons are in the nucleus of a carbon-14 atom?
14 - 6 = 8 neutrons
State one difference and one similarity between Rutherford's model and Bohr's model
Similarity: small dense nucleus, atom is mostly empty space
Difference: Bohr's model shows different energy levels for electrons, while Rutherford's does not.
Electrons are found in ___________.
the electron cloud
Elements in the same group have the same number of ____________.
How many electrons would S2- have?
16 + 2 = 18 electrons
Chlorine exists in two isotopes: Cl-35 and Cl-37. Based on the average atomic mass on the periodic table, which isotope is more abundant? How do you know?
Cl-35, because the average atomic mass is closer to 35 than 37
Which model would be best to show the arrangement of electrons into energy levels?
Bohr model - it is the only one that shows discrete energy levels
How many electrons can be in the first energy level? The second?
First - 2
second - 8
What halogen has 4 levels of electrons?
bromine
Determine the number of protons, neutrons, and electrons in the following:
35Cl-
protons: 17 (atomic number)
neutrons: 35 - 17 = 18
electrons: 17 + 1 = 18
The most common isotope of bromine has how many neutrons?
45 (avg mass rounds to 80, 80 - 35 = 45)
Which model was originally developed to explain the presence of negative particles in a cathode-ray tube?
The plum pudding/JJ Thomson's model
Like charges repel each other. What keeps the protons in the nucleus from flying apart?
The strong nuclear force
The heaviest alkali metal is ___________
francium (Fr)
A calcium atom has 18 electrons - what is its charge?
20 protons - 18 electrons = +2 charge
How is the average atomic mass shown on the periodic table determined?
The weighted average of the masses of all the different isotopes of an element.