chem flashcards

matter

a substance that has volume and has a space

atom

building block of matter

mixtures

consists of 2 or more types of particles that are not chemically combines together

Pure substances

a substance that is made up of only one particle throughout

molecules

2 or more atoms that are covalently bonded

compound

2 or more atoms that are ionically bonded

protons

positively charges subatomic particles that are situated in the middle of the atom

neutrons

neutral subatomic particles that are situated in the middle of the atom

electrons

small negatively charges subatomic particles that revolve around the atom

atomic number

the number of protons in the nucleus of the atom

mass number

the total number of protons + neutrons in the nucleus

atoms are electrically neutral

this means that the number of electrons equals to the number of protons

isotopes

atoms that have the same number of protons but different numbers of neutrons

valence electrons

the number of electrons in the final shell of an atom

Ion

a positively or negatively charges atom

cation

a positively charges ion the atom loses electrons

anions

negatively charged ion the atom gains electrons

metals

they have loosely held valence shells and alway lose electrons to become cations

non-metals

they have tightly held valence electrons and alway gain electrons to become anions

transition metals

they have really big valence shells so they can lose or gain electrons really easily and have variable charges

ionic compound/ionic bonds

typically forms when a metal reacts with a non metal and metals transfer electrons to nonmetals

properties of ionic bonds

• high melting and boiling points

• hard and brittle

• insulators when solid

• conductors when molten or dissolved

• crystal lattice structure

metallic ions

they carry a positive charge as they have donated electrons to a non metal

properties of metals

• lustrous

• good conductors of heat and electricity

• malleable and ductile

• high melting/boiling points

alloys

a mixture of two or more elements where one element is a metal combined via metallic bonding

covalent bonding

occurs between two non metals where atoms share electron pairs

diatomic molecules

covalent bonds with the same elements