elements, compounds and mixtures Flashcards
patterns in the periodic table
Going up or down a column, elements are organised into groups which have similar chemical properties
metals on the left - non metals on the right - metalloids on the staircase
Moving left or right within a row, the atoms trend smaller or larger in size, and their reactivities go up and down.
metals vs non metals
metals - lustrous . malleable . conductors of heat and electricity . ductile . solid at room temp (not mercury)
non metals - poor conductors of heat and electricity . dull . brittle
elements weight
weight left to right
protons
positive charge . found in the nucleus
nuetrons
neutral charge . found in the nucleus
electrons
negatively charged . found in electron clouds orbiting the nucleus.
element
A substance that cannot be broken down into simpler substances by chemical means.
compound
a substance made from two or more different elements that have been chemically joined. can only be separated chemically
mixture
a combination of two or more pure substances in which each pure substance retains its individual chemical properties . can be separated physically
single atoms
the smallest unit at the atomic scale, consisting of a single isolated atom
molecules
he smallest unit at the atomic scale, consisting of a single isolated
Complex molecules are made up of more than two atoms of the same or different elements eg., calcium carbonate,. They tend to have stronger bonds than simple elements.
lattices
grid like structure made up of singular atoms. examples of lattices are diamonds or graphite.
mixtures vs compounds
compounds are chemically bonded where as mixtures are physically bonded
recognising elements on the periodic table
8 <——— atomic number
O <——— Atomic symbol
oxygen <- element symbol
16 <——– atomic mass
atomic number
number of protons in the nucleus
