2: Atoms Flashcards
Democritus
All matter is made up of very small particles
Atoms from atomos “not to cut”
Element
Substance that consists of identical atoms
Compound
Pure substance made up of two or more elements in a fixed ratio by mass
ELEMENTS IN THE HUMAN BODY
1. Big Four
C
H
N
O
ELEMENTS IN THE HUMAN BODY
2. Next Seven
Ca- strengthens bones; aids blood clotting
P- phosphates of bones, nucleic acids, energy transfer
K- regulate electrical balance of fluids; nerve conduction
S- component of proteins
Cl- necessary for growth and development
Na- regulate electrical balance
Mg- helps nerve and muscle action; present in bones
ELEMENTS IN THE HUMAN BODY
3. Trace Elements
Cr
Co
Cu
F
I
Fe
Mn
Mo
Zn
Mixture
Combination of two or more pure substances
Dalton’s Atomic Theory
- All matter is made up of tiny indivisible particles, atoms.
- All atoms of same element have same chemical properties.
- Compounds are chemical combination of different kinds of atom.
- Molecule is tightly bound combination of atoms that act as single unit
EVIDENCE FOR DALTON’S ATOMIC THEORY
1. Law of Conservation of Mass
-Antoine Lavoisier
-Matter can neither be created nor destroyed.
EVIDENCE FOR DALTON’S ATOMIC THEORY
2. Law of Constant Composition
-Joseph Proust
-any compound is always made up of elements in the same proportion by mass
Diatomic Elements
H
O
N
Cl
Br
I
F
Polyatomic
Ozone, O3
Phosphorus, P4
Diamond, millions of carbon atomd
Etc.
Atomic mass unit (amu)
-scale of relative masses of atoms
1 amu= 1.6605x10^(-24)
-mass exactly equal to 1/12 mass of one Carbon12 atom
Mass number
number of protons and neutrons in the nucleus of an atom
Atomic number
Number of protons in the nucleus of an atom
Isotopes
-Same number of protons but different number of neutrons; different atomic mass
-rejects second statement of Dalton’s atomic theory