Vocabulary 1
the amount of matter in an object
What is mass
a reaction that gives off heat
what is exothermic
What is the formula to find an object’s density
density = mass/volume
What do atoms of the same element have the same number of
the same number of protons
How is the periodic table organized
it is arranged by atomic mass
a positively charged particle inside an atom’s nucleus
what is proton
a reaction that absorbs heat
what is endothermic
What is true about chemical bonds
Chemical bonds result from electrical attraction between atoms
When does a replacement reaction take place
It takes place when elements replace each other
a chemical combination of two or more elements
what is a compound
a negatively charged particle that moves around an atom’s nucleus
What are the noble gases?
Noble gases make up the last column of the periodic table. They are the most stable elements. They rarely react with other substances.
If blue litmus paper turns red what can you infer about the solution? If red litmus paper turns blue what can you infer about the solution? If no reaction occurs what can you infer about the solution
If it turns red, the solution is an acid. If it turns blue the solution is a base. If no reactions occurs the solution is neither an acid nor a base.
the amount of space an object takes up
what is volume
a group of tightly bonded atoms that acts like a single particle
what is molecule
the amount of mass in a certain volume of material; found by dividing the mass of an object by its volume
what is density
an electrically charge particle with unequal numbers of protons and electrons
what is ion
What are the characteristics of metals? Nonmetals?
Metals – good conductors, change chemically when exposed to air, not brittle, bendable
nonmetals – not good conductors, don’t change chemically when exposed to air, brittle, not bendable
Tell what colloids, emulsions, and suspension are and give an example of each one. What do they have in common?
They are all types of mixtures.
Colloid – contains undissolved particles that stayed mixed in another substance (ex: fog)
emulsions – a suspension of 2 liquids that usually do not mix together (ex:oil and salad dressing)
suspension – mixture made of parts that separate upon standing (ex: soil and water)
Tell how the model of an atom changed over the years? How does this change illustrate the importance of communicating the results of a scientific experiment?
Starting from the 1800s scientists continued to discover more about atoms
and change the model. As new information is gathered or old information
is changed, ideas changed. It leads to greater understanding.