WorksheetsElements
Total questions: 26
Worksheet time: 14mins
All atoms of the same element must have the same number of
Protons
Neutrons
Compounds
Electrons
An atom of the element zinc has an atomic number of 30 and a mass number of 65. How many protons does an uncharged zinc atom have?
30
35
65
95
Scientists in a lab are working with two different samples of the element mercury. They know that the different samples are different isotopes. Which property of the isotopes must be different?
the atomic number
the electric charge
the element name
the mass number
When an atom that has no charge loses two electrons, it becomes a
positive ion
negative ion
positive isotope
negative isotope
A researcher is using a particle accelerator in an experiment studying isotopes. How can the researcher change one isotope into a different isotope of the same element?
by adding valence electrons
by removing valence electrons
by adding and removing protons
by adding and removing neutrons
The symbol P represents the element phosphorus. This element’s atomic number is 15. How many protons and electrons are in a P–3 ion?
15 protons and 3 electrons
12 protons and 15 electrons
15 protons and 18 electrons
18 protons and 15 electrons
What can be added to an atom to cause a nonvalence electron in the atom to temporarily become a valence electron?
energy
mass
neutrons
electrons
The model below shows a carbide ion. What could be done to change this carbide ion to a neutral carbon atom?
remove 2 electrons
add 2 electrons
remove 4 electrons
add 4 electrons
Uranium is an element that is often used in nuclear power plants. Uranium atoms are very large, and the substance can be dangerous if it is not carefully contained.What is true about all uranium atoms?
They each have the same number of nuclear particles
They each have the same number of neutral particles.
They each have the same number of neutrons.
They each have the same number of protons.
One way in which elements differ from each other is the structure of the electron cloud in each element’s atoms. In an electron cloud, an electron that is farther away from the nucleus has
a greater charge than an electron near the nucleus.
a smaller charge than an electron near the nucleus
a higher energy than an electron near the nucleus.
a lower energy than an electron near the nucleus.
The model below shows a calcium atom. How many electrons are in the third energy level?
2
8
18
20
All atoms of the element potassium have 19 protons. One of the most stable types of potassium atoms has the mass number 39. How many neutrons make up one of these potassium atoms?
19
20
38
58
One isotope of sodium has 11 protons and 7 neutrons. What is the mass number of this isotope?
4
7
11
18
Some isotopes of elements are unstable and decay into other, more stable isotopes over time. For example, it takes 153 years for half of a sample of silicon (Si) atoms with 14 protons, 14 electrons, and 18 neutrons to decay.
What is the name of this specific silicon isotope?
silicon-14
silicon-32
silicon-46
silicon-153
All large radioactive atoms decay into smaller atoms by releasing alpha particles. Each alpha particle has 2 protons, 2 neutrons, and 0 electrons. The table below describes several neutral, low-mass atoms.An alpha particle is also referred to as a nucleus of which isotope?
lithium-7
helium-4
hydrogen-2
helium-2
A potassium atom (atomic number 19) and a bromine atom (atomic number 35) can form a chemical bond through a transfer of one electron. The potassium ion that forms has 18 electrons. What best describes the bromide ion that forms?
It is a negative ion that has one less valence electron than a neutral bromine atom.
it is a positive ion that has one less valence electron than a neutral bromine atom.
It is a negative ion that has one more valence electron than a neutral bromine atom.
It is a positive ion that has one more valence electron than a neutral bromine atom.
The simple model below is a neutral magnesium (Mg) atom with the element’s most common mass number.What must happen to an atom of magnesium in order to become a magnesium ion Mg+2?
It must lose two neutrons and become a different isotope.
It must gain two neutrons and become a different isotope.
It must lose two electrons and become an ion.
It must gain two electrons and become an ion.
The chemical symbol for the element calcium is Ca. What would be the symbol representing calcium atoms that have lost two electrons?
Ca–
Ca+
Ca–2
Ca+2
Scientists are working with a liquid that is made of only one type of atom. Which statement correctly describes this liquid?
The liquid contains only one compound.
The liquid contains only one element.
The liquid contains only neutral electrons.
The liquid can be broken down into simpler substances.
Which are different forms of an element that have different numbers of neutrons?
ion
isotopes
compounds
molecules
What is the number at the end of an isotope’s name?
atomic number
neutron number
mass number
electron number
Which describes an atom that has fewer neutrons than protons and more electrons than protons?
negative compound
positive compound
positive ion
negative ion
An atom of the element chromium has an atomic number of 24 and a mass number of 52. How many electrons are in an uncharged atom of chromium?
0
24
28
52
Atoms of two different elements must have different
electrical charges.
numbers of neutrons.
atomic numbers.
energy levels
What is the atomic number of this atom?
6
8
9
16
Which have different numbers of electrons?
different ions of an element
different isotopes of an element
the nucleus of an element
each of the atoms of an element
