Chemical Bonds and Chemical Reactions

element

substance (atoms or molecules) composed of a single type of element

product

substance which results from the breaking and making I chemical bonds in a chemical reaction

chemical reaction

the interaction of atoms and molecules which results in the making or breaking of chemical bonds, resulting in a new substance. Also called a "chemical change."

the first row (vertical) in the periodic table is....

the most reactive out of all the other ones

chemical bonding is determained by _______________

the number of electrons in the valence level

what order does the electrons order upen in each shell

2 8 8

ionic bond

a chemical bond in which one atom donates electrons to another atom to complete its valence shell

covalent bond

a chemical bond in which two atoms share a pair of electrons to complete the valence shell of both atoms

endothermic reaction

a chemical reaction which must absorb heat to power the reaction

exothermic reaction

a chemical reaction which releases heat to the environment

chemical bonding

a process by which atoms form chemical bonds which result in a new substance

Lewis dot diagram

a shortcut for showing the valence electrons of an atom: chemical symbol surrounded by the valence electrons only of the atom

chemical change

a substance undergoes a change which results in a different (new) substance. Also called a chemical reaction

stable

an atom with a full valence level. only atoms with I filled valence levels are unstable and will try to bond with other atoms to make new substances

neutral

an atom with the same number of protons and electrons, resulting in a charge of zero

chemical bond

an attractive force which holds atoms together

what does the air around an endothermic reaction feel like

cold, it uses the heat around the reaction to 'power' it

matter is...

composed of atoms and groups of atoms bonded together, called molecules

chemical equation

describes what happens to a chemical reaction using reactants and products

valence electrons

electrons in the outermost (valence) energy level of an atom; the only electrons involved in chemical bonding

molecule

groups of atoms chemically bonded together into a unique, new substance

what does the air around an exothermic reaction feel like

hot, it produces its own hear

what are the 2 types of chemical bonding

ionic and covalent

what does the arrow mean in a chemical equation

it shows that the substance underwent change and what is on the other side is not the same as what it was in the beginning

law of conservation of mass

matter (mass) can neither be created nor destroyed. it can, however, be rearranged

Ionic compounds occur when...

metals react with nonmetals ●Metals lose electrons and become positive ions ●Nonmetals gain electrons and become negative ions •Examples: NaCl CaCl2

compound

molecule made of more than one type of atom chemically bonded together

are molecules more stable when they are not bonded together

no

valence level

outermost energy level of an atom

Atoms interact through the...

process of chemical bonding.

reactants

starting materials of a chemical reaction

octet rule

the valence level is full when it has 8 electrons (exception: energy level 1 is full with 2 electrons) which results in a stable atom

what is the order of where to put the dots on the lewis dot diagram

top, bottom, right, left, top, bottom, right left

what is a single bond

when one pair of electrons are shared between two atoms

unstable atom

when the valence level is NOT full

stable atom

when the valence level is full

what is a double bond

when two pairs of electrons are shared

are compounds only molecules

yes

covalent bonds always occur when...

•Always between nonmetals. •Formed by sharing electron pairs •Examples O2 CO2 H2O

CHEMICAL REACTION (CHEMICAL CHANGE) IS

•occurs when bonds are created OR broken between atoms. •The result is ALWAYS a new substance