Essay About Atomic Number And Protons Electrons

Econ AP
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Atoms
Smallest unit of matter
Made of protons electrons and neutrons
Has protons and neutrons packed together in a nucleus
The electrons orbit around
Atomic number
Written as a subscript next to the symbol of an element
Number of protons (and hence number of electrons) of a neutral elements atom
mass number
sum of protons and neutrons, written as a superscript to the left of an elements symbol
atomic weight
approximation of the total mass of an atom
isotopes- atoms of the same element that have a different number of neutrons and hence weigh more.
Can be:
stable
radioactive
the nucleus decays spontaneously
energy levels
energy- ability to do work
different electron orbitals with different states of potential energy are energy levels
electrons on outermost orbitals are valence
electrons have orbitals
2 electrons per orbital
an almost defined area in which electrons can travel
can be more than one orbital per shell
Molecules
Atoms connected by chemical bonds
Covalent bond
Sharing of a pair of valence electrons by two atoms
More than one pair of electrons can be shared
The number of covalent bonds an atom can make is called its valence
i.e. oxygen has a valence of 2
there can be polar covalent bonds
electro negativity is the attraction of an atom for the covalently bonded electrons
nonpolar covalent bonds have equally electronegative covalently bonded atoms
ionic bonds
where