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