2. formulae and symbols

Formulae and

symbols for atoms and compounds

Elements are pure substances that cannot be broken into simpler matter through chemical processes.

• Smallest building blocks of elements

• Smallest particle• Identical in a specific element• Differ in size, mass and

properties in different elements

Atoms

• Period 2: 2 orbitals

• 6 protons• 6 electrons• 12-6 = 6

neutrons• Group 4: 4

valence electrons +

+++ ++

Symbols and what they tell you:

OThe element oxygen2 2+2 Two oxygen

atoms bonded together, forms a molecule

Electric charge when oxygen accepts e-

Two

sepa

rate

par

ticle

s of

what

ever

follo

ws.

O2-

O2-

O2-

2O2-

O2

2O2

• Smallest particles of a compound.• Two or more atoms that

are chemically bonded together.• Molecules of the same

compound are identical.• Atoms in molecules are

in a fixed ratio.Molecules

Diatomic molecules

Compounds

Compounds are pure substances that can be broken/separated into simpler matter through chemical processes.

elements Bond to form compoundsMade up of Made up of

atoms Molecules of

compoudsMolecules of atoms

Chemical bonding

Slide 1: http://nurul.kimia.upi.edu/arsipkuliah/web2011/0900721/images/18.png Slide 2: http://3.bp.blogspot.com/-XArs98-ZAzc/Uaq8qqx9rKI/AAAAAAAADBM/KIsAfqCTD2Q/s1600/Elementos+2.jpg Slide 3: vid: https://www.youtube.com/watch?v=IixqvhxQMNs gif: http://makeagif.com/2wTBNH Slide 4: http://sciencenotes.org/wp-content/uploads/2013/06/PeriodicTable-NoBackground2.png Slide 6 - 8: ion: http://duch.sd57.bc.ca/~rmcleod/Chemists_Corner/Bohr_Chalco_Ion_files/Oxide.jpg Slide 9: Atoms: http://biowiki.ucdavis.edu/@api/deki/files/2722/oxygen_molecule,_O2.gif?size=bestfit&width=387&height=213&revision=1 Spacefill model: https://upload.wikimedia.org/wikipedia/commons/c/c0/Oxygen_molecule.png Slide 10: https://upload.wikimedia.org/wikipedia/commons/c/c0/Oxygen_molecule.png Slide 11&13: gif: http://makeagif.com/Ogv1rT vid: https://www.youtube.com/watch?v=QqjcCvzWwww Slide 12: http://s3.amazonaws.com/engrade-myfiles/4005492574704763/compounds_molecules.jpg Slide 14: http://i0.wp.com/www.sciencemusicvideos.com/wp-content/uploads/2014/07/01_methane-formula-explained.png Slide 15: http://www.bbc.co.uk/staticarchive/4e1862d0b757481990a81c6eebea40179f88903a.gif