Basic chemistry review and water molecule bonding

All matter is made of particles, molecules, atoms If you enlarged a gold nucleus to 2 feet across, the outermost Electron would be 3.3 miles away! If you shrunk the sun to 2 feet across, the earth would be only 215 feet away, And Pluto would be only 1.6 miles away! An atom is more spread out than our own solar system!!

Atoms! All atoms are made up of 3 parts (which do have smaller parts but we don’t need to worry about those yet). –Electrons –Protons –Neutrons I’m really MUCH smaller than this!

Electrons! -Very, very, small mass (negligible) –negatively charged –Free to move around the atom

Protons -Much larger mass than electron -positively charged, same level of charge -stuck in the nucleus.

Neutrons! –Larger than Proton –no electrical charge at all

What can you change about yourself, your appearance and still be ‘YOU’? Your hairstyle Some plastic surgery Your weight But you are still you, right? What if you could change something as fundamental as your DNA?

Atoms can also change… Can lose or gain electrons –Ex: sodium loses an electron so it is charged positive +1 –STILL SODIUM, but an ION of sodium!! Can lose or gain neutrons ex: sodium gains a neutron so its atomic mass increases STILL SODIUM, but an ISOTOPE of SODIUM!!

What part of an atom is like its DNA? The protons!!! If an atom loses or gains protons, its entire identity changes!! Example: carbon somehow loses a proton…it becomes Boron, atomic # 5!!

In electrical charges, and in magnetism ‘Like’ or ‘same’ repels. ‘Unlike’ or ‘opposite’ attracts. A positive charge on an proton is equal to the negative charge on the electron. One proton’s + cancels out one electron’s -

How do protons, electrons and neutrons stay together yet apart? It’s a tricky balancing act!! Protons in the nucleus repel each other What keeps them from flying apart and joining the electrons? **A force in the nucleus called ‘The Strong Force’

How do atoms make molecules, compounds? Atoms use the electrons on the outside! –Give or take –sharing The force that makes atoms combine is –The pull of electrical charge

Water! Source of all life!! Chemical formula H 2 O –2 hydrogen and 1 oxygen atom –covalent sharing of electrons.

A closer look While a water molecule doesn’t normally look this way, but for convenience it is drawn this way.

COVALENT BONDING in water If 2 atoms like to steal… they often keep stealing electrons back and forth. These atom’s end up sharing electrons.

Sharing…..is it always equal? The Bus Seat Analogy Not Equal – polar Example - water Equal – non-polar Example - oil

Water is polar Oxygen ____________ Hydrogen _____________ That makes O – That makes H +

Positive since there are no electrons to cancel the proton More electrons then protons means more negative

Positive and negative sides Water is attracted to itself! In fact it loves itself. Positive hydrogen are attracted to the negative oxygen

Bonding between water molecules hydrogen bonds

Water has interesting properties All of water’s properties can be explained by either the –Hydrogen bonding between molecules –Covalent bonding inside the water molecule