As a Matter of Fact
Matter cannot be created or destroyed, but it can change forms
What is the law of conservation of mass?
Atoms of an element with the same number of protons but different numbers of neutrons
What are isotopes?
Rows of the periodic table
What are periods?
The sum of protons and neutrons in the nucleus
What is the mass number?
Around 400, B.C., he said atoms were smallest unit of matter.
Who was Democritus?
What is an atom?
The abbreviation of an element found on the periodic table
What is a symbol?
Columns of the periodic table
What are groups?
Electrons that are in the highest energy level of an atom
What are valence electrons?
Who was Aristotle?
Anything that has mass and takes up space
What is matter?
Determines an element's chemical properties
What is the number of valence electrons?
The elements in group 1A
What are the alkali metals?
The number of protons in an atom
What is the atomic number?
His experiments provided evidence that atoms contain negatively charged particles.
Who was J.J. Thompson?
Matter that cannot be separated into any other substance and alway has exactly the same composition
What are pure substances?
The most reactive group of elements
What are the alkali metals?
The elements in group 8A
What are noble gases?
A region of space around the nucleus where electrons are most likely to be found
What are orbitals?
Conducted the gold foil experiment and found evidence of a nucleus
Who was Ernest Rutherford?
Contains two or more substances
What is a mixture?
The symbol Au comes from this Latin word for gold.
What is aurum?
The elements in group 3A
What is the Boron group?
Subatomic particles that have opposite charges
What are protons and electrons?
Developed a method of organizing elements that is still used today with some revisions
Who was Mendeleev?