Atoms Introduction

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

• No charge

• A negative charge

• A positive and a negative charge

• A positive charge

Neutrons are in the nucleus of the atom. A neutron has

• A positive charge

• No charge

• A negative charge

• Twice as much positive charge as a proton

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

• 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 in the atom's nucleus

• 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 that 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

The atomic number of nitrogen is 7. The atomic mass is 14.01. This means that

• All nitrogen atoms have exactly 7 neutrons.

• A small percentage of nitrogen atoms have fewer than 7 neutrons

• A small percentage of nitrogen atoms have more than 7 neutrons

• Some nitrogen atoms have fewer than 7 electrons