Atomic structure

what are atoms

what are atoms

very small particles made up of three main subatomic particles (protons, neutrons and electrons)

where are protons and neutrons found in an atom

in the nucleus (small dense central region)

charge of a proton

+1

charge of a neutron

0

charge of an electron

-1

where is the electron found in an atom

outside the nucleus (on shells)

which one is the mass number and the atomic number

why is the nucleus positively charged

it contains positively charged protons and neutral neutrons

why are all atoms neutral

they contain equal numbers of positively charged protons and negatively charged electrons

what is the atomic number

the number of protons in the nucleus

what is the mass number

number of protons plus the number of neutrons in the nucleus

what are elements

substances made up of only type of atom

how to figure out no. of neutrons of an atom

mass no. - atomic no.

what are isotopes

atoms with the same number of protons but different numbers of neutrons

why do isotopes of an element have different masses

due to the different numbers of neutrons in their nuclei

why do isotopes of an element behave the same way in chemical reactions

since the number of electrons determines the way an atom reacts (have same no. of electrons and protons - atomic no.)

what differs or stays the same between isotopes of an atom

different - no. of neutrons

same - no. of electrons and protons

how to figure out no. of protons of an atom

mass no. - no. of neutrons (atomic no. = no. of protons)

order of maximum electronic configuration

2,8,8,2

what do lewis diagrams include

only valence electrons

what are valence electrons

electrons in the outer most shell (highest occupied energy level)

what number of valence electrons is not exceeded

past 8 valence electrons

what electrons are involved in chemical reactions

only valence electrons

what tends to happen when atoms have the same number of valence electrons

they have similar chemical properties

what is the period of a periodic table

the same row across the periodic table

what is the group of a periodic table

same column down the periodic table

how to figure out valence electrons for group 1 and 2

no. of valence electron = group number eg. group 2 has 2 valence electrons

how to figure out valence electrons for group 13 to 18

no. of valence electron = group number - 10 eg. group 17 has 7 valence electrons

what does the number of valence electrons do across a period

increases

what does the number of valence electrons do down a group

remains the same

what are cations

positively charged ions (have fewer electrons than protons)

when do cations form

when atoms or a group of atoms lose electrons

what are anions

negatively charged ions (have more electrons than protons)

what groups of the periodic table are metals found in

groups 1, 2 and 13

what trend do metals usually do (link cations)

tend to lose electrons to form monatomic cations (one atom)

what groups of the periodic table are non-metals found in

groups 15, 16 and 17

what trend do non-metals usually do (like anions)

tend to gain electrons to form monoatomic anions

whats special about group 18 elements

they are unreactive towards most other elements (do not tend to from ions)

what are polyatomic ions

ions that consist of a stable group of atoms with an overall charge eg. NH4

what is the valency of an ion

the magnitude or size of the charge of the ion eg. sodium ion valency is +1

what can transition metals do

can form a range of cations with different valencies eg. copper or iron

what groups are non-metals found

groups 14-17