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An atomic particle has a net charge of zero and is found in the nucleus. Which of the following particles is it?
What is the mass number of an element numerically equal to?
The atomic mass of a neutral atom of the element
The number of neutrons in a neutral atom of the element
The number of protons plus neutrons in a neutral atom of the element
The number of electrons in a neutral atom of the element
An atom of element X contains 16 protons and 18 neutrons. What would the mass number of an atom approximately half as heavy as an atom of X be?
The number of electrons and the mass numbers of a series of particles are shown in the following table. (The symbols used, U to Z, are not the correct symbols for the elements.)
X and Z
U and Y
W and Y
V and X
When describing the sizes of atoms, a very useful unit is the nanometre. Nanometres are one-thousandth of a micrometer, μm. Most human eyes cannot see objects smaller than the width of a human hair, which is 50 μm. How can the width of a human hair also be expressed?
5.0 × 10−2 cm
5.0 × 104 nm
5.0 × 10−6 m
Which list of subshells is ranked in order of increasing energy?
2s < 2p < 4p < 3d
1s < 2p < 3d < 4s
1s < 1p < 1d < 1f
2s < 3p < 3d < 4p
What is the maximum number of electrons that can occupy an orbital in the 4p subshell of an atom?
Atomic number is
The number of protons and electrons
The number of protons in the nucleus of an atom
The number of protons and neutrons in the nucleus of an atom
The number of electrons and neutrons
Which of the following lists is ordered from smallest to largest?
width of a human hair, bacterium, oxygen molecule
red blood cell, oxygen molecule, helium nucleus
proton, electron, cell nucleus
cell nucleus, oxygen molecule, width of a human hair
Which of the following equation is true where A=atomic number, P=proton number, N=neutron number, M=mass number?
have a nucleus that occupies most of the atom’s volume.
are all the same size.
contain only protons in their nucleus.
have most of their mass in the nucleus
A nanometre is
one billionth of a metre.
one hundredth of a metre.
one thousandth of a metre.
one hundred thousandth of a metre.
What is the nanometre scale in centimetres?
Which of the following is the correct ranking of prefixes from largest to smallest when they refer to particle size?
Nano, micro, kilo
Nano, kilo, micro
Micro, kilo, nano
Kilo, micro, nano
In the nucleus of an atom are 11 protons and 12 neutrons. What is its mass number?
Which of the following statements regarding subatomic particles is correct?
Protons are positively charged particles and neutrons are negatively charged.
The relative masses of an electron, a proton and a neutron are all about 1 unit.
In a neutral atom, the number of neutrons is equal to the number of protons.
Isotopes of an element have the same number of protons but different numbers of neutrons.
What did Bohr’s theory of the atom propose?
Electrons orbit the nucleus like planets move around the sun.
No more than two electrons are allowed in any energy level.
Electrons move around the nucleus in fixed orbits, each of which has a different energy level.
Energy shells have subshells that contain regions of space called orbitals.
What is the maximum number of electrons that can be placed in the shell n = 3?