chemistry
what is an element
a pure substance that cannot ne broken down inti anythung simple by either physical or chemical means
atomic mass
number of protons and neutrons in the nucleus
atomic number
protons in the nucleus. top corner
atom
smallest part if a particle. atill has properties if an elemeny
what are atoms made out of
subparticles
what are the charges
positive protron
negative electron
nuetral neutrons
where is the nucleus
centre if atom
how many electrons are in an atom
how ever many protons
whats matter
anythibg tayt has mass and takes up space
what properties dies matter have
physical and chemical
examples of physical properties
hardness, melting and boiling point, odour, solubility, colour
whats a physical change
a chnage in size or form of a substance
shat change does NOT change a substance to a new substance
chemical property
starting melting point called
reactants
new materials called
products
who gave us the periodic table
Dmitri Mendeleev
how is the periodic table organized
based in chemical properties and and the increase in a period manner
groups are
colomns
periods are
rows
mettalloid is
has soem properyies kf metal and is diagonally beside metals