What is matter?
Anything that has mass and occupies space.
What physical states is matter found in?
What are elements?
Substances that cannot be broken down into other substances.
What is an atom?
The smallest unit of matter that still retains the properties of an element.
What is a proton?
A subatomic particle w/ a single unit of positive electrical charge (+)
What is an electron?
A subatomic particle w/ a negative charge.
What is a neutron?
an electronically neutral subatomic particle.
What makes up the nucleus?
Protons and neutrons.
What is the atomic number?
The number of protons in an atom.
What determines which element it is?
the atomic number.
What is mass?
The sum of the number of protons and neutrons in its nucleus.
How many of the 90 naturally- occuring elements are used by living organisms?
What are the 4 most abundant elements in living cells?
Oxygen, carbon, hydrogen, and nitrogen.
What are isotopes?
Elements that exist in different forms
Forms of an element that differ in mass
Same num of protons and electrons but diff num of neutrons
What is a radioactive isotope?
is one in which the nucleus decays, giving off particles of energy.
What primarily determines how an atom behaves?
Which part of the atom has the most energy?
The outer shell.
The number of shells an atom has depends on what?
the number of electrons it has.
How many electrons can the inner shell of an atom hold?
How many electrons can the 2nd and 3rd shell of an atom hold?
up to 8 electrons.
What determines the chemical properties of an atom?
The number of electrons in the outermost shell.
What are the three types of chemical bonds?
What is an ionic bond?
The attraction btwn opposite charged ions.
What is a covalent bond?
Forms when 2 atoms share 1 or more pairs of outer shell electrons and forms a molecule.
What is a hydrogen bond?
Formed when a particularly positive atom from one polar molecule is attracted to the partially negative atoms in another molecule.
What is ion?
The term for atoms that are electronically charged as a result of gaining/losing electrons.
What is an ionic compound?
A compound held together by ionic bonds.
What is a molecule?
Atoms held together by covalent bonds.
The number of covalent bonds an atom can form is equal to what?
The number of additional electrons needed to fill its outer shell.
What is a polar molecule?
a molecule that has opposite charges on opposite ends.
What is a chemical reactions?
Changes is the chemical compound of matter.
The bond between the hydrogen atom of one water molecule and the oxygen atom of another water molecule is made possible by
the polarity of the water molecule
The tendency of water molecules to stick to each other is called