8-Chemistry*
What determines the cohesiveness of water molecules?
hydrogen bonds
Which of the following trace elements needed by humans is commonly added to table salt?
iodine
Electrons have a ________ charge.
negative
The hydrogen bond between two water molecules forms because water is:
polar.
If you place a feather on the surface of a bowl of water, the feather remains suspended on the surface due to the:
surface tension of the water.
Which of the following is an example of hydrogen bonding?
the bond between O of one water molecule and H of a second water molecule
Max number of electrons in inner and outer shells?
Inner-2 Outer-8
The tendency of water molecules to stick together is referred to as
cohesion.
Water moves through a plant because of the property of:
cohesion.
hydrogen bond
weak attraction between a hydrogen atom and another atom
Water's life supporting
1. Cohesive Nature 2. Ability to Moderate Temperature 3. Floating Ice 4. Water as a solvent
The sodium atom contains 11 electrons, 11 protons, and 12 neutrons. What is the mass number of sodium?
23
The second electron shell of an atom can hold a maximum of ______ electron(s).
8
Base
A substance that decreases the hydrogen ion concentration in a solution.
Acid
A substance that increases the hydrogen ion concentration of a solution.
Isotopes
Atoms of the same element that have different numbers of neutrons.
Neutrons have a ________ charge.
Neutral or no
Four Elements Essential for Life
Oxygen, Carbon, Hydrogen, Nitrogen
Protons have a _______ charge.
Positive
Atom
Smallest particle of an element
What is it about carbon-12, carbon-13, and carbon-14 that makes them all carbon?
They all have the number of protons that is characteristic of carbon.
covalent bond
a bond formed when atoms share one or more pairs of electrons
ionic bond
chemical bond formed when one or more electrons are transferred from one atom to another
Nucleus of an atom
contains protons and neutrons
atomic number
the number of protons in an atom
chemical reaction
the process by which one or more substances change to produce one or more different substances
mass number
the sum of the number of neutrons and protons in an atomic nucleus
