WARM UP 9/18

1.1. How did you do on your test? Predict your How did you do on your test? Predict your grade.grade.

2.2. How long did you study? How long did you study? 3.3. Is there anything you could have done better to Is there anything you could have done better to

prepare?prepare?4.4. Summarize in three sentences or less what you Summarize in three sentences or less what you

learned from chapter 1.learned from chapter 1.5.5. Write 5 things that come to mind when I say Write 5 things that come to mind when I say

“chemistry”.“chemistry”.

NOTES 9/18 CH2: CHEMISTRY OF LIFE

BIOCHEMISTRY

The chemistry of living things.The chemistry of living things.

History of the ATOM

460 BC – 460 BC – DEMOCRITUSDEMOCRITUS

*matter divided until *matter divided until smallest partsmallest part

““atomos” – unable to cutatomos” – unable to cut

1800’s – DALTON1800’s – DALTON

*basic unit of all matter *basic unit of all matter is atomsis atoms

* solid, undividable * solid, undividable particlesparticles

1900’s – 1900’s – RUTHERFORDRUTHERFORD

• Spheres with mostly Spheres with mostly spacespace

• Smaller particles in Smaller particles in themthem

Subatomic articles – parts in an atom

1.1. Proton + chargeProton + charge

2.2. Neutron no chargeNeutron no charge

3.3. Electron - chargeElectron - charge

ATOMIC NUMBER

# of protons in an atoms# of protons in an atoms

Makes each atom Makes each atom differentdifferent

Most atoms neutral, so Most atoms neutral, so

# protons = # electrons# protons = # electrons

ION – an atom with a charge because of too many or not enough electrons

(makes the atom more reactive)

ANION – Too many e- , so charge is negativeANION – Too many e- , so charge is negative

CATION – Not enough e-, so charge is positiveCATION – Not enough e-, so charge is positive

ATOMIC MASS (NUMBER)

Total number of Total number of protons and neutrons protons and neutrons in an atomin an atom

ELEMENT – substance made of only one kind of atom

EXAMPLE

6

Carbon

C12.001

2.4

Atomic

Number

Atomic Mass Number

Element

Periodic Table

1869 – MENDELEEV1869 – MENDELEEV

Organizes all the Organizes all the elements in a elements in a systematic way systematic way

In order of atomic In order of atomic numbernumber

PERIOD – each row PERIOD – each row across across

7 periods7 periods All elements in same All elements in same

row are in same periodrow are in same period

GROUP - (family)GROUP - (family) Each column Each column

Elements in same Elements in same group have similar group have similar propertiesproperties

18 groups18 groups

2 main groups – metals 2 main groups – metals and nonmetalsand nonmetals

Hydrogen acts as bothHydrogen acts as both

ASSIGNMENT

ElementElement symbolsymbol groupgroup periodperiod Atomic Atomic ##

Mass Mass ##

# # protonsprotons

Metal or Metal or nonmetalnonmetal

% of % of bodybody

O, C, H, N, Ca, P, K, S, Na, Cl, Mg, I, Fe

O 65%O 65% S .3%S .3%

C 18.5%C 18.5% Na .2%Na .2%

H 9.5%H 9.5% Cl .2%Cl .2%

N 3.2%N 3.2% Mg .1%Mg .1%

Ca 1.5%Ca 1.5% I .1%I .1%

K .4%K .4%

Fe .1%Fe .1%

P 1%P 1%

ASSIGNMENT 9/17 Finish chart – front and back – show me todayFinish chart – front and back – show me today

Page 34-36 READ – WRITE QUESTIONSPage 34-36 READ – WRITE QUESTIONS 1. How many electrons in an atom?1. How many electrons in an atom? 2. How many e- can the 12. How many e- can the 1stst shell hold? shell hold? 3. The 23. The 2ndnd shell? shell? 4. The outermost shell?4. The outermost shell? 5. What is important about the # and arrangement of e- in an 5. What is important about the # and arrangement of e- in an

atom’s outermost shell?atom’s outermost shell? 6. When is an atom chemically reactive?6. When is an atom chemically reactive? 7. What does chemically reactive mean?7. What does chemically reactive mean? 8. What if the e- in the outer shell are paired?8. What if the e- in the outer shell are paired?