Ch2 Flashcards
(8 cards)
1
Q
How many naturally occurring elements are there?
A
92
2
Q
Atomic # is = to…
A
of protons
3
Q
Atomic mass is = to…
A
Sum of protons & neutrons
4
Q
What is a Chemical Bond?
A
Compounds of 2 or more elements bound together.
5
Q
What is a Ionic Bond?
A
Attraction of oppositely charged ions
Ex. Na+Cl-
6
Q
What is a Covalent Bond?
A
When two atoms share their outer shell electrons to make them stable
*Atoms held together by covalent bonds forms a molecule!
7
Q
What is Hydrogen bonding?
A
The partial positive charge hydrogen on a water molecule is attracted to the partial negative charge of the oxygen on another water molecule
8
Q
Name the properties of water
A
- Cohesion=water molecules like to stick together. Hydrogen bonding
- Surface tension=Insects walking on water without breaking the surface
- Moderate temperature=water absorbs and stores a lot of heat, evaporative cooling
- Ice floating=water is less dense as a solid
- Water is liquid at room temperature=Hydrogen bonding between water molecules
