Download •What makes up an atom? Draw an atom

SCIENCE STARTER #1 – 9/21/16
• What makes up an atom? Draw an
atom
• GRAB A NEW GREEN SHEET FROM THE FRONT
• TAKE OUT YOUR COVER PAGE TO BE STAMPED
NOTES 2.1: CHEMISTRY
CHAPTER 2 PG. 31-35
LIFE IS MADE OF ATOMS
• Smallest unit is an atom
• Nucleus: center/core is most of
the mass of the atom
• protons: + (positive)
• neutrons: 0 (neutral)
• Orbital: outer region
around the nucleus
• electrons (e-): - (negative)
WE ARE MADE OF ELEMENTS
• Element - Pure substance that can’t be
broken into other types of matter
• Each element has its own symbol and specific
number of protons
• Atomic number: number of protons
• Atomic mass: number of protons + neutrons
IONS
• Ion: charged atom due to gaining or losing
electrons
• Remember electrons are negative
• Lose e-, ion will be POSITIVE
• Gain e-, ion will be NEGATIVE
• Ex. Na+, Cl-, Ca2+
ISOTOPES
• Isotope: different number of neutrons changes
the mass, but NOT the element
• EX. C12 vs C14
• Carbon 14 is
heavier since
it has two more
neutrons
COMPOUNDS
• Compound: substance made up of 2 or more
elements
• Compound behave differently than individual
elements
• EX. Na vs NaCl
COMPOUNDS
• Compounds are held together by bonds
• Covalent bonds (strong): 2 or more atoms
share electrons
• Ionic bonds (weak): attractions between +
and – ions by transferring electrons
PROPERTIES OF WATER
• Water has a positive (+) and a negative (-)
pole
• Pulls apart ionic molecules like NaCl
WATER BONDING
• Hydrogen bonds: bonds BETWEEN water
molecules (the hydrogen from one water
molecule bonds with the oxygen from
another water molecule)
• Bond strength:
• Covalent > Ionic > Hydrogen
CHEMICAL REACTIONS (RXN)
• NaOH + HCl  NaCl + H2O
•
Reactants
Products
• Activation energy: amount of energy
needed to start the reaction
• Reactants: compounds that are
rearranged
• Left side
• Products: compounds that are created
• Right side
CHEMICAL REACTIONS (RXN)
• NaOH + HCl  NaCl + H2O
•
Reactants
Products
• Exergonic/exothermic: release energy like
heat, explosion, light etc. – feels hot
• Endergonic/endothermic: requires energy to
occur and takes it from the environment –
feels cold
ACTIVATION ENERGY
• Activation Energy (EA) - energy
needed to start a reaction
NEED TO MEMORIZE THE FOLLOWING
ELEMENTS AND COMPOUNDS FOR
YOUR QUIZ AND TEST!
• ELEMENTS
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H: hydrogen
O: oxygen
N: nitrogen
C: carbon
Na: sodium
Cl: chlorine
K: potassium
S: sulfur
• COMPOUNDS
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H2O: water
NaCl: sodium chloride/salt
H2SO4: sulfuric acid
HCl: hydrochloric acid
NaOH: sodium hydroxide
CO2: carbon dioxide
• O2: oxygen gas