Chapter 1
The number of protons an element has.
Molecules
What are chemical properties of elements?
Flammable A color change usually indicates a chemical reaction.
96% of the human body is made up of the elements oxygen, ______________
Oxygen, nitrogen, hydrogen, and carbon
Explain how scientists are able to ‘see’ atoms.
Atoms are too small to be seen with the eye. Scientists have developed technology that allows them to make images of atoms and molecules. This technology finds the shape of an atom or a molecule and then displays it on a computer screen.
What is an alloy and why did humans create them?
Alloys are made by mixing a metal with another element. People make alloys because they have properties that are more useful than the individual metals that formed them. Examples of alloys are : steel, brass, bronze
What characteristic was used to arrange elements on the Periodic Table?
Elements on the periodic table are arranged by their atomic number.
Elements in the columns of the Periodic Table share what property?
They share chemical properties.
Since Helium has the atomic number 2, what can you infer about its number of protons?
It has 2 protons.
Which metal is liquid at room temperature?
Mercury
What property of metals make them useful in electronics?
They are good conductors of electricity.
What are the physical characteristics of metals? (Based on this information, you should be able to infer what the physical properties of nonmetals may be)
The physical characteristics of metals include: malleable (they can bend) Ductile (can be made into wires) Good conductors of electricity Shiny ◦ Non-metals are opposite. Bad conductors of electricity.
What is the solute in sea water?
Salt
Write the chemical formula for water.
H20
What compound makes up more than 60% of the human body?
Water
If you were to look at the periodic table, what assumptions can you make about where an element is placed on the table. If you were to look at Argon, what can you write about this element?
It is a non-metal It is in group 18 (noble gases) It has an atomic number of 18 which means it also has 18 protons.
Give an example of a molecule that is not a compound.
Examples: Hydrogen, nitrogen, oxygen, gold
Write about the information a scientist might find useful about an element on the Periodic Table.
Atomic number Atomic weight Symbol