Ch. 12 Atoms (Finals)
Some alpha particles fired through a gold foil bounce backward by
1. making direct hits with gold atoms 2. electrostatic repulsion when close to gold nuclei 3. electrostatic repulsion with the electron clouds of gold atoms.
The atomic number of fluorine is 9 and its mass number is 19, so it has
10 neutrons
Compared to the mass of a hydrogen atom, the mass of an oxygen atom is __ times greater.
16
If lithium has a mass number of 7 and an atomic number of 3, a lithium atom contains
3 protons, 4 neutrons, and 3 electrons
a certain atom has 26 protons, 26 electrons, and 30 neutrons. Its mass number is
56
atomic symbol
One or two letters used to represent an atom of a particular element
Electrons differ from protons and neutrons because electrons have
a much smaller mass
One atomic mass unit describes the mass of
a proton or neutron
Nuclei of atoms that make up a newborn baby were made in
ancient stars
electrons
atomic particles found in energy levels outside the nucleus.
neutrons
atomic particles that are electrically neutral
isotopes
atoms whose nuclei contain the same number of protons but different numbers of neutrons.
If a pair of helium nuclei are fused together, the result is
beryllium
If two protons are removed from an oxygen nucleus, the result is
carbon
What is it that electrons have that protons always have in equal magnitude? 1. mass 2. charge 3. energy 4. all of these 5. none of these
charge
a particle that moves around the nucleus is an
electron
Each energy level of an atom has a maximum number of __ it can hold
electrons
Since boron has an atomic number of 5, it has five
electrons
The chemical properties of matter comes mostly from its
electrons
The volume of matter comes mostly from its
electrons
An electric force between the nucleus of an atom and its electrons causes the
electrons to movie in an orbit around the nucleus
to change mercury into gold, a pair of protons must be removed form the mercury atoms? (True or False)
false
Most alpha particles fired at a gold foil pass through undeflected because the
gold atoms , like any others, are mostly empty space
Because the nucleus of an atom contains protons, it
has a positive charge
If one neutron is added to helium nucleus, the result is
helium
The atomic number of an element tells
how many protons are in its nucleus
Atoms of the same element with different numbers of neutrons are called
isotopes
Which has the greatest number of protons in its nucleus? 1. gold 2. mercury 3. lead 4. silver
lead
The Bohr Model of the atom is similar to a
miniature solar system
The reason a gravity block is mostly empty space is because the atoms in the gravity are
mostly empty space themselves
A chemical symbol represents the __ of an element.
name
If two protons are added to an oxygen nucleus, the result is
neon
Which of the following are electrically neutral: 1. proton 2. neutron 3. electron 4. all of these 5. none of these
neutron (2)
Atoms heavier than hydrogen were made by
nuclear fusion
In an electrically neutral atom, the number of protons in the nucleus is balanced by an equal number of
orbital electrons
Dot diagrams are used to represent
outer electrons
The weight of matter comes mostly from its
protons
The nucleus of an atom is made up of
protons and neutrons
The mass of an atom, in atomic mass units, is equal to the number of
protons and neutrons in its nucleus
Particles of matter that make up protons and neutrons are
quarks
Brown motion has to do with the
random motions of atoms and molecules
Assuming all the atoms exhaled by Julius Caesar in his last dying breath are still in the atmosphere, the we probably breathe one to those atoms with each
single breath
If we doubled the magnifying power of the most powerful optical microscope in the world, we would
still not be able to see an atom
atomic mass
the average of all masses of the isotopes of a particular element.
What makes an element distinct?
the number of protons
Compared to the atoms that make up the body of an elderly person, the atoms that make up the body of a newborn baby are
the same age
mass number
the sum of the protons and neutrons in the nucleus of a particular kind of atom
There are about as many atoms of air in our lungs at any moment as there are breaths of air in the atmosphere of
the whole world
J.J Thomson's discovery of negatively charged particles in atoms indicated that
there are smaller particles than atoms
How many different elements are in a water molecule?
two`
Which of these atoms has the greatest number of electrons? 1. helium 2. carbon 3. iron 4. gold 5. uranium
uranium
Which of these atoms has the most mass? 1. hydrogen 2. iron 3. lead 4. uranium 5. all of the same mass
uranium
Because atoms are too small to study directly, scientists
use models of atoms
