UNIT 1: 2.0 Chemical Foundations of Life -> 2.1 Atoms, Isotopes, Ions, and Molecules: The Building Blocks

Matter

Anything that takes up space and has mass

Elements

are unique forms of matter with specific chemical and physical properties that cannot be broken down

Atoms

• is the smallest unit of matter that retains all of the chemical properties of an element.

  Which consist of protons, neutrons, and electrons, are the smallest units of matter that retain all their characteristics and are most stable when their outermost or valence electron shells contain the maximum number of electrons.

what two regions atoms are composed to?

nucleus which is in the center of the atom and contains protons and neutrons, and the outermost region of the atom which holds its electrons in orbit around the nucleus.

Proton

is positively charged

Neutron

is uncharged.

Electrons

can be transferred, shared, or cause charge disparities between atoms to create bonds, including ionic, covalent, and hydrogen bonds, as well as van der Waals interactions.

Isotopes

Are different forms of an element that have different numbers of neutrons while retaining the same number of protons; many ____, such as carbon-14, are radioactive.

The Periodic Table

Molecules

are simply two or more atoms chemically bonded together

Bohr Model

shows electrons orbiting the nucleus of an atom

Octet rule

elements will gain, lose, or share electrons to complete their valence shell and become stable (like noble gases)

Chemical Bonds

: an attraction between two atoms, resulting from the sharing or transferring of valence electrons

Electronegativity

: the measure of an atom’s ability to attract electrons to itself

Covalent bonds

when two or more atoms share electrons (usually between two nonmetals)

There are two types of covalent bonds:

polar and nonpolar

Nonpolar covalent

form between two atoms of the same element or between different elements that share electrons equally.

Polar covalent

Electrons are not shared equally between two atoms

Ionic bonds

are formed between ions with opposite charges.

Hydrogen bonds

 The partially positive hydrogen atom in one polar covalent molecule will be attracted to an electronegative atom in another polar covalent molecule