periodicity Flashcards
(26 cards)
what is the covalent radius
half the distance between the nuclei of two covalently bonded atoms
what happens to covalemt radius as we follow a period left to right
covalent radius decreases
why does covalent radius decrease along the way
atom size is decreasing, because the nuclear charge of protons in the nucleas have a stronger pull on electrons
what happens to covalent radius as we go down the periodic table
covalent radius increases
why does covalent radius increase going down the periodic table
atom size increases, as there is more shells around the nucleas causing shielding outer shell electrons are further away from nucleus
how can atoms become ions
by gaining or losing electrons
why do atoms become ions
to become more stable by having 8 electrons in their outer shell
how do metals and non metals become ions
metals lose electrons and become positive ions
non metals will will gain electrons and become negative ions
what is the first ionisation energy
the energy required to remove one mole of electrons from one mole of atoms in the gaseous state
why is energy required to remove an electron
it is held to the atom by the attraction to the positive nucleus
what happens to ionisation energy as you go down a group
it decreases
why does ionisation energy decrease as you go down a group
electrons are further away from the nucleas so experience a shielding effect
why does ionisation energy increase as you go along a period
nuclear charge increases as number of protons increase causing electrons to be held with greater force
why does removing an electron from a full shell require more energy
atoms want to remain stable
what is electronegativity
a measure of the attraction an atom has for the electrons involved in a bond
what happens to electronegativity as you go along a period
it increases
why does electronegativity increase as you go along
nuclear charge increases
what happens to electronegativity as you go down a group
it decreases
why does electronegativity decrease as you go down
due to the atoms having more occupied electron shells
what do melting and boiling points depend on
strength of forces which exist between the particles which make up a substance
what is the melting/boiling point for a covalent network and why
high , it is a strong covalent bond
what is melting/boiling point for covalent molecule and why
low, its intermolecular forces
what is the melting/ boiling point for monatomic
low, as its intermolecular forces
what does melting and boiling points depend if elmer’s show from left to right
elements on the left have stronger forces of attraction than those on the right
