key area 2 chemistry

Atomic Structure and Bonding

What is a column and a row in the periodic table as?

Column=Group Row=period

where should elements be if they have similar chemical properties

in the same group (column)because they have same number of outer electrons

how many elements are present when the compound ends in -ide

only 2 elements

how many elements are present when the compound ends in -ate or-ite

at least 3 elements where 1 element is oxygen

name the 3 sub particles

protons,electrons and neutrons

state the location,charge and mass of a proton

inside nucleus,1+,1 amu

state the location,charge and mass of an electron

outside nucleus in energy levels,1-,0

state the location,charge and mass of a neutron

inside nucleus,neutral(no charge),1 amu

why are atoms neutral?

because they have the same number of positive protons as negative electrons so they cancel out

what does diatomic mean?

2 atoms bonded together in a molecule

state the seven diatomic elements

Hydrogen,iodine,nitrogen,chlorine,bromine,oxygen,fluorine

name the group 1,group 7,and group 0 elements and state their reactivity

G1=alkali metals (reactive), G7=Halogens (reactive) ,G0=Noble gases (unreactive beacuse they have a full outer electron shell)

what is the atomic number equal to?

Atomic number =number of protons

what is the mass number equal to?

mass number=number of protons + number of neutrons

how would you work out the number of protons in an atom

number of protons= atomic number

how would you work out the number of electrons in an atom?

number of electrons=atomic number

how would you work out the number of neutrons in an atom?

number of neutrons=mass number-atomic number

what is an ion?

a charged atom

why does an atom form an ion?

an atom changes into an ion to achieve the same stable electron arrangement as a noble gas

does a metal atom become positively charged ion by losing or gaining electrons?

losing electrons

does a non metal atom become negatively charged ion by losing or gaining electrons?

gaining electrons

what are isotopes?

atoms with the same atomic number but different mass numbers

when given 2 or 3 isotopes and the relative atomic mass how do you work out which isotopes is the most abundant?

for 2 isotopes-choose mass number closest to the RAM as most abundant.

For 3 isotopes-ignore middle one then choose the mass number closest to the RAM as most abundant

what is the relative atomic mass of an element?

average mass of all the isotopes of that element

draw the electron arrangement diagram of a) nitrogen b)magnesium

what type of elements do covalent bonds form between?

non metal elements

how does a covalent bond form?

a covalent bond forms when 2 positive nuclei are held together by their common attraction for a shared pair of electrons

name 2 types of structure a covalent substance can form?

discrete molecular structure and network structure

why do covalent molecular substances have low melting and boiling points?

only weak forces of attraction between the molecules are broken when a substance changes state not the strong covalent bonds within the molecules.

why do covalent network structures have very high melting and boiling points

the network of a strong covalent bonds needs lots of energy to break them.

are covalent substances soluble in water?

no they are insoluble in water

why do covalent substances not conduct electricity?

they don’t conduct electricity because there are no changed particles which are free to move

what type of elements do ionic bonds form between?

metal and non metal elements

what are ionic bonds?

electrostatic attraction between positive and negative ions

name the type of structure an ionic substance can form?

lattice

why do ionic compounds have high melting and boiling points?

strong ionic bonds must be broken in order to break up the lattice

are ionic substances soluble in water?

soluble in water (lattice breaks up allowing water molecules to surround separated ions)

why do ionic compounds conduct electricity only when molten or in solution?

the lattice structure has broken up allowing ions to be free to move.

why do ionic compounds not conduct electricity when solid?

ions are not free to move

what is electrolysis?

a process which uses electricity to break down an ionic compound into its elements

why is DC supply used during electrolysis experiments?

to identify the products .

why are the carbon electrodes used in electrolysis experiments?

they are good conductors,unreactive and insoluble

what is the electrolyte?

the ionic solution that electricity is passing through.

in the electrolysis experiment what type of ion is attracted to the negative electrode?

positive ion

in an electrolysis experiment what type of ion is attracted to the positive electrode?

negative ion.