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Essential Question: What are the differences and similarities among living
things?
Unit: Chemistry of Life, Chapter 2
Atom:
basic unit of matter, made of 3 subatomic particles (smaller than
atom)
Proton:
positively charged subatomic particle, found in nucleus, number of
protons = mass number, where it is found on periodic table
Neutron:
neutrally charged subatomic particle, found in nucleus
Nucleus:
center of atom
Electrons:
negatively charges subatomic particle
ex. Carbon atom
element:
made of 1 atom, pure substance
isotope:
atoms of same element with different numbers of neutrons
ex. Carbon 12= 6 protons, 6 neutrons, 6 electrons
Carbon 13= 6 protons, 7 neutrons, 6 electrons
Carbon 14= 6 protons, 8 neutrons, 6 electrons
Radioactive isotope:
nuclei unstable, breaks down over time, scientists use for finding age
of rocks and fossils, kill and treat cancer
Compound:
substance formed by the chemical combination of 2 or more
elements. Ex. H20, NaCl
**The physical and chemical properties of compounds are usually
very different for the elements they are formed from.
Chemical bonds
(2 types)
1) Ionic bonds:
electrons transferred
2) Covalent bonds:
Ions:
electrons shared
positively or negatively charged atoms
Molecule:
result of covalent bonding
Summary: What would a molecule of water look like? Draw it with
chemical bonds-