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
What is a chemical bond?
Force that joins atoms
True or false: because they have the same number of electrons, all isotopes of an element have the same chemical properties.
True
Give examples of ways radioactive isotopes are used in scientific and practical uses
To determine the ages of rocks and fossils. Radiation from certain isotopes can be used to detect and treat cancer. Also to kill bacteria that cause food to spoil. Can be used as labels or tracers to follow the movement of substances within organisms
What is a compound?
Substance made of the joined atoms of two or more elements.
How is a compound represented?
By a chemical formula that identifies the elements in the compound and their proportion
True or false; the physical and chemical properties of a compound are usually very different from those of the elements from which it is formed
True
What are the main types of chemical bonds?
Ionic bonds and covalent bonds
What are the electrons that are available to form bonds called?
Valance electrons
What is an ionic bond?
Is formed when one or more electrons are transferred from one atom to another
What is an ion?
The positively and negatively charged atoms
What is the proportion of the following compounds? NaCl, H2O, CO2
1 to 1, 2 to 1, 1 to 2
What is covalent bond?
Two or more atoms that share electrons
What is the difference between a single and double covalent bond?
A single covalent shares two electrons but a double bond shares four electrons
What is a molecule?
A group of atoms held together by covalent bond; they are the smallest unit of most compounds
Which level of electron has the least amount of energy?
Inner level - energy increases as you move to outer layers
How many electrons are in rows 1,2 and 3?
Row 1 - 2, row 2 - 8, row 3 -8
True or false: an atom becomes stable when the outer electron level is empty
False
What happens when the outer level of an atom is not full?
It will transfer or share electrons so it can become full
What is a cation?
Lost electron (+)
What is an anion?
Gained electron (-)
Van der Waals forces are what?
Slight attraction between oppositely charged regions of nearby molecules
