atoms, elements, and molecules

Question 1

atoms overview
Protons
Neutrons
Electrons
Valence Electrons
Number of protons
Atomic Mass
Atomic Number
HONC PS

Answer 1

atoms overview
- Protons: found in the nucleus of an atom (positive charge)
- Neutrons: no charge
- Electrons: found outside of the nucleus (negative charge)
- Valence Electrons: found on outermost shell
- Tells us how many bonds the atom can make and types of compounds it will form
- Number of protons = number of electrons
- Atomic Mass: protons + neutrons (decimal number below element symbol)
- Atomic Number: number of protons in an atom (number directly above element symbol
- HONC PS - found in all living things
Hydrogen, oxygen, nitrogen, carbon, phosphorus, sulfur

Question 2

element vs. compounds

Answer 2

• Elements - pure substances that are composed of only type of atom (i.e. oxygen, hydrogen)
• Compounds - substances that are formed by two or more different types of elements (i.e. carbon dioxide, water)
  - United chemically

Question 3

bond

Answer 3

• Covalent Bond - strong bond between two atoms (atoms share electrons)
  - C-C Bonds
• Hydrogen Bond - weak bond between water molecules

Question 4

water

Answer 4

Polar molecule because it is unevenly charged
- Oxygen side - negative
- Hydrogen side positive

Question 5

water properties

Answer 5

• Cohesion: the property of molecules sticking together
• Adhesion: attraction between molecules of different substances
• Universal Solvent: Water’s polarity gives it ability to dissolve ionic compounds+other polar molecules

Question 6

buffers

Answer 6

• Weak acids/bases that can resist sudden changes in pH and keep it close to neutral
• Body must maintain homeostasis in blood and cells or else cellular reaction will not occur