Science - Atoms

Protons are located in the nucleus of the atom. A proton has

• a positive charge

• no charge

• a negative and positive charge

• a negative charge

Neutrons are in the nucleus of an atom. A neutron

• has a positive charge

• no charge

• a negative charge

• twice as much positive charge as a protoon

An electron is in a region outside the nucleus. An electron

• is larger than a proton and has no charge

• has less mass than a proton and has a negative charge

• is smaller than a proton and has no charge

• has a positive charge

A hydrogen atom is made up of one proton and one electron. The proton and electron stay near each other because

• because positive and negative charges repel

• positive and positive charges repel

• positive and negative charges attract

• two negatives make a positive

The atomic number of an atom is

• the mass of the atom

• the number of protons added to the number of neutrons

• the number of protons

• negatively charged

The atoms of the same element can have different isotopes. An isotope of an atom

• is an atom with a different number of protons

• is an atom with a different number of neutrons

• is an atom with a different number of electrons

• has a different atomic number

The atomic mass of an element is

• the average mass of all the isotopes of the element

• a measure of the density of that element

• the mass of the most common isotope of that element

• the number of protons and electrons in the atoms of the element

An element and an atom are different but related because

• a particular element is made up of many different types of atoms

• a molecule is the same as an atom

• an element is made up of all the same type of atom

• an element is smaller than an atom

The periodic table shows that a carbon atom has six protons. This means that a carbon atom also has

• six electrons

• six neutrons

• more protons than electrons

• an atomic mass that equals six

Electrons are in regions around the nucleus called energy levels. The first energy level

• is the furthest from the nucleus

• is closest to the nucleus

• holds the most electrons

• needs more than two electrons fill it up