2.1 - The Nature Of Matter Flashcards
What is an atom?
The smallest unit of matter that cannot be broken down by chemical means.
What are the 3 subatomic particles of an atom?
Protons, Neutrons, Electrons
The charge of a proton?
Positive
What is the charge of a neutron?
No charge (neutral)
What is the charge of an electron?
Negative
Are found in the space around the nucleus(electron cloud) in constant motion
What is the nucleus? What is it made of?
The center of the atom made of protons and neutrons
What 2 subatomic particles are attracted to each other? Why?
Protons and electrons
They are oppositely charged
Compare the numbers of elections and protons
They are typically the same causing the atom to have no charge.
What is an element?
Substance made of only one kind of atom (pure substance)
What is an atomic number?
Number of protons in the nucleus of an atom
How many elements are there?
118 distinct atoms: 90 natural, 28 created in laboratory
What is the atomic symbol of an element?
1, 2, 3 letter symbol used to represent elements
What is an isotope?
Atoms of an element that contain different numbers of neutrons
What is the mass number?
Number of protons plus the number of neutrons
Used to identify isotopes
What does radioactive isotopes mean?
The nuclei are unstable and break down at a constant rate over time