chapter 2 biology test Flashcards
A substance that cannot be broken down into anything else
Element
Composed of two or more elements that are chemically combined (not a mixture)
Compound
Protons + neutrons
Atomic mass
____ of an atom have a different number of neutrons which vary their atomic mass
Isotopes
____ elements have a full outer shell so they don’t react with other elements
Inert
The atoms boned by and ionic bind are called a __________
Formula unit
____ bonds form when electrons are shared between two elements
Covalent
Two or more atoms held together by covalent bonds
Molecule
Covalent bonds are _____ than ionic bonds
Stronger
An atoms attraction for electrons
Electronegativity
_____ covalent bonds form when there is an unequal sharing of electrons
Polar
Covalent bonds have an equal sharing of electrons between two atoms of the same elements
Non polar
Weak attraction between polar molecules (usually water)
Hydrogen bonds
Acids have a pH ____ than 7
Less
Bases have a pH _____ 7
Above
_____ allows water molecules to form hydrogen bonds with each other
Polarity
The properties of wanted help it support ____
Life