Introduction to Chemistry

Bonds

Atoms combine with each other by forming bonds, which create molecules or formula units

Electronegativity

the relative ability of an atom to attract electrons towards itself in a chemical bond

Bonds

Atoms combine with each other by forming bonds, which create molecules or formula units

Electronegativity

the relative ability of an atom to attract electrons towards itself in a chemical bond

ionic

a transfer of one or more valence electrons from one atom to another

Ions

charged particles with an unequal number of protons and electrons

covalent bond

two atoms are sharing valance electrons with each other

polar covalent bond

an unequal sharing of electrons between two atoms of unequal electromagnetivity

nonpolar covalent bond

two atoms are either of the same element or have very similar electroagnitivy

double bond

two pairs of electrons (four electrons total) are shared between two atoms

Tripe bond

three pairs of electrons (six electrons total) are shared between two atoms

nonpolar covalent bond /\EN

0-0.4

polar covalent bond /\EN

0.4-2.0

ionic bond /\EN

2.0>

molecule

two or more atoms covalently bonded together, can be atoms of the same, or different elements

compound

a substance made up of two or more different kinds of atoms.

valence electrons

the electrons that can be used to form bonds with other atoms.

Activation energy

Energy needed to get a reaction started

Endergonic

energy-absorbing reactions (Photosynthesis is an endergonic reaction requiring energy from sunlight)

Exergonic

energy releasing reactions (Cellular respiration is an exergonic reaction that releases the energy stored in food to generate many ATP molecules)

All reactions require an input of energy

Atoms have to collide with each other fast enough in the proper orientation to reach a transition state

Chemical reaction

Process that changes one set of chemicals into another set of chemicals (there is a change in the way atoms are bonded together)

Atoms are more stable (lower energy state)

Full valence shell of electrons

Ionic bond forms

When there is a large electronegativity difference between two atoms

Proton

positive charge, in the nucleus

cation

positively charged ion

anion

negatively charged ion

buffer

prevents sudden/rapid changes in a pH.

Atomic Mass Number

# of protons + # of neutrons

Atomic Mass

average atomic mass number of all the isotopes of an element 

coefficient

number in front of the bond to show the number of molecules

subscript

little number next to the element to show the number of atoms in a single molecule of the bond

Water

Held together by polar covalent bonds; has hydrogen bonds(between water molecules); amphiteric

amphoteric

a liquid that can act as an acid and as a base

cohesion

the attraction between molecules of the same substance

surface tension

the surface of a liquid is able to resist an external force; caused by cohesion

Capillary action

the ability of a liquid to flow upwards despite gravity; caused by adhesion and cohesion

adhesion

attraction between molecules of different substances; stuck together with hydrogen bonds

Solution

Group of molecules evenly mixed

Solute

substance to be dissolved

Solvent

substance doing the dissolving (since water is polar, it dissolves polar and charged solutes very well!)

hydration sphere/hydration shell

shell around each ion, separating and stabilizing each ion.

Heat of vaporization

the amount of energy a substance must absorb to change state from a liquid to a gas.

evaporative cooling

as a liquid evaporates, its remaining surface cools

isotope

an atom with the same number of protons but a different number of neutrons

Bohr Model

Shows the number of protons and neutrons in the nucleus and the electrons in their shells around the nucleus, Shows all of the electrons

Lewis Dot Structure

Element symbol in middle, Shows only valence electrons

universal solvent

many different substances dissolve in water