Section 1 and Section 2 - Directed Reading for Content Mastery

The nuclei of all atoms of a give element always have the same number of ________.

Protons

The electrons has very little mass compared to the ____ or _______.

Protons, neutrons

________ and _________ make up the nucleus and are made up of ________.

Protons, neutrons, quarks

The mass of the atom depends on the nucleus and how many _________ and _________ it has.

Protons, neutrons.

They will also have the same number of _________ around the nucleus.

electrons

Atoms of the same element with different numbers of neutrons are called ________.

isotopes

The mass of the atom is so small that there is a measure called the atomic ________ unit designated by amu.

mass

Some atoms may have more or fewer _ than will other atoms of the same element.

neutrons

The sum of the protons and neutrons is the mass ________ of an atom.

number

There are ______ uniquely different quarks.

six

Every atom of carbon must contain _________ but some contain six neutrons and others have eight neutrons.

six protons

________ are found in an area around the nucleus called the ____________.

Electrons, electron cloud