Chemical Formulas and Names Flashcards
what are the two types of compounds?
- ionic compounds
- covalent compounds
what is in ionic bonding?
-electrons are transferred from metal to non metal atoms
how is an ionic bond formed?
- by the attraction between positive and negative ions
- made up of metal and non metal
steps to write ionic compounds?
- write metal ion
- write non metal ion
- change non metal ending to ide
why must the positive charges balance the negative charges in an ionic compound?
-the overall charge is zero
what are metals with more than one ion charge?
-multivalent metals
how to know which ion of a multivalent metal to use for a specific compound?
-roman numerals in the name
what do roman numerals show?
-the charge of the metal ion
when is a roman numeral needed?
-when an element has more than one possible ion charge
when is a roman numeral not needed?
-when an atom only has one possible ion charge
what are polyatomic ions?
- several atoms joined tgt with covalent bonds
- the whole group has a charge not the individual atoms
when to use brackets around polyatomic ions?
-when there is more than one in the formula
how to know if you are dealing with a polyatomic ion?
-there are more than two elements or the formula contains three or more capital letters
if a polyatomic ion has a positive charge what does it act as?
-metal
if a polyatomic ion has a negative charge what does it act as?
-non metal
what do the molecules in covalent compounds do?
-share electrons
covalent bonds occur between?
-two or more non metals
what do prefixes indicate?
- number of atoms in the molecule
- written before atom name
naming covalent compound steps?
- use prefixes to show amount of each atom
2. change ending of second atom to ide
what happens if there is only one atom of the first element?
-no prefix is used
-what does the chemical formula of a covalent compound tell us?
-number of atoms of each element in the compound
what do ionic compound subscripts show?
-smallest whole number ratio between the ions in the compound
what do covalent compound subscripts show?
-the actual number of atoms in the molecule
what do lewis diagrams show?
-arrangment of valence electrons around the nucleus of an atom
what are not shown in lewis diagrams?
-inner electron shells with electrons
what happens after bonding in LD?
-no more electrons are shown in the ion
LD shortcut for metals?
-always have no electrons
LD shortcut for non metals?
-always have full shell of electrons
if there is more than one non metal how should it be drawn?
-separated
what is there not in covalent compounds?
-no transfer of electrons or ions
what are bonding pairs?
-electron pair being shared between the two non metals
what are lone pairs?
-pairs of electrons that aren’t shared (2)
how many diatomic elements are there?
- 7
- hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine
what do diatomic elements never occur in?
-single atom
when are they most stable?
- when bonded with another atom of the same element
- they create double bonds
what do diatomic elements consist of and why can they be called diatomic molecules?
- consists of two atoms
- have a covalent bond
what is a chemical change?
- changes that produce new kinds of matter with different properties
- new substance created
- process known as chemical reaction
- is not easily reversed
what is a physical change?
- change that does not produce new substances
- temperature, size, physical state can be altered
- can be easily reversed
examples of chemical changes?
- digesting food
- burning match
- milk sours
- cooking of food
- chemical reaction
examples of physical changes?
- boiling liquid
- cutting paper
- freezing water
- silver melting
- paper towel absorbs water
