key concepts in chemistry Flashcards
what are the charges and masses of protons, neutrons and electrons?
proton:
mass 1 charge +1
neutron:
mass 1 charge 0
electron:
mass 1/1836 charge -1
how did Mendeleev arrange the periodic table
he arranged it in order of atomic mass and left gaps for unknown elements
when metals react what ion do they form?
positive ions
what is ionic bonding?
the transfer of electrons between a metal and a non metal
what is an ion?
an atom or group of atoms with a positive or negative charge
if a compound ends in ide how many elements does it contain?
2
if a compound ends in ate how many elements does it contain?
3 (one of them is oxygen)
what are the properties of an ionic compound?
- metal+non-metal
- regular structure
- strong electrostatic forces of attraction
- high mp/bp
- conduct when molten/dissolved
what is covalent bonding?
the sharing of electrons between two non metals
what is the formula for methane, hydrogen, hydrogen chloride, water, oxygen, carbon dioxide?
methane CH4
hydrogen H2
hydrogen chloride HCl
water H2O
oxygen O2
carbon dioxide CO2
what are the properties of simple molecular compounds?
- weak intermolecular forces
- do not conduct
- insoluble in water
what are the properties of giant covalent structures?
- high melting points
- strong covalent bonds
- some conduct electricity
what are metals made up of?
positive ions in a sea of delocalised electrons allowing them to conduct electricity
structure of diamond
made of carbon atoms- each carbon makes 4 bonds
very hard
can be used in cutting tools
do not conduct
structure of graphite
made of carbon atoms- each carbon makes 3 bonds
soft
conducts
made in sheets
used in pencils
