Matter
What is matter?
Matter is anything that has mass and takes up space.
What Is a Proton?
•Positively charged particles.
•Help make up the nucleus of the atom.
•Help identify the atom
•Equal to the atomic number of the atom.
•Contribute to the atomic mass.
•Equal to the number of electrons.
What is the number of protons in Na?
What element is this?
Protons = 12
electrons = 12
Magnesium
What Is an Atom?
An atom is the smallest whole particle of matter.
What Is a Neutron?
•Neutral particles; have no electric charge.
•Help make up the nucleus of the atom.
•Contribute to the atomic mass.
What is the number of electrons in Carbon?
6
Where is each subatomic particle located in the atom?
Protons → In the nucleus (center of the atom)
Neutrons → Also in the nucleus
Electrons → In orbitals or energy levels around the nucleus
What are subatomic particles?
Subatomic particles are smaller than atoms and are the tiny particles that an atom is made of.
What Is an Electron?
•Negatively charged particles.
•Found outside the nucleus of the atom.
•Move so rapidly around the nucleus that they create an electron cloud.
•Equal to the number of protons.
•Involved in the formation of chemical bonds.
What is the number of neutrons in oxygen?
8
When is an atom neutral?
When the number of protons = number of electrons
Their opposite charges cancel each other out.
What Is the Nucleus of an Atom?
The central part of an atom.
Composed of protons and neutrons.
Contains most of an atom's mass.
What is the charge on each subatomic particle?
Proton = +1 (positive)
Neutron = 0 (neutral)
Electron = –1 (negative)
What does the letter Z represent?
atomic number
Which subatomic particles affect the identity of an element?
The protons determine what element it is.
Example: All atoms with 6 protons are carbon.
How can you determine how many electrons are in an atom?
atomic number and number of protons
How can you determine the number of protons in an atom?
atomic number
What does the letter M represent?
Mass number of the atom
Which subatomic particles have the largest impact on the mass of an atom?
Protons and neutrons
Electrons have almost no mass, so they barely affect the total.