BONDING, STRUCTURE & PROPERTIES OF MATTER Flashcards
(20 cards)
When are ions formed
when atoms gain or lose electrons
properties of ionic compounds
high melting and boiling points
conduct elec when melted or in water - ions free to move
ionic bonds = vv strong
correct formula for a nitrate ion:
NO3-
Hydroxide ion
OH-
Sulphate ion
SO4^2-
whats empirical formula
simplest, whole number ratio of atoms of each element in a compound
what is covalent bonding
sharing electrons
three types of substances covalent bonds can make
simple molecular substances
larger structures (e.g. polymers)
giant covalent structures (e.g. diamond, graphite)
Covalent bonds form between ________ atoms.
non-metallic
properties of covalent atoms
low melting + boiling points - IMF’s are weak
bonds = vvv strong but weak forces between molecules IMF
what happens to boiling point as you go down group 7
increases
properties of simple molecular substances
Strong covalent bonds between the atoms of each molecule.
Weak intermolecular forces between molecules.
Low melting and boiling points (so normally gaseous as room temperature).
Cannot conduct electricity.
properties of giant covalent structures
Every atom is connected by strong covalent bonds
No weak intermolecular forces as there is only one structure
High melting and boiling points
Cannot conduct electricity (except graphite)
what state are simple molecular subatnces at room temp
gas
Do giant covalent structures have high or low melting points?
high
properties of diamond
each carbon atom covaently bonded to 4 other carbon atoms
pyramid shape
high melting point
doesn’t conduct elec - no free ions
properties of graphite
Structure:
Each carbon atom bonds to 3 others → forms layers of hexagons
1 delocalised electron per atom
Properties:
Conducts electricity – due to free electrons
Slippery/lubricant – layers slide over each other (weak forces between them)
High melting point – strong covalent bonds
Soft – used in pencils
Two substances made from the same element, that are in the same physical state, but that have different structures, are called
_____
allotropes
can diamond conduct elec
no
