Atom
How are protons, neutrons, & electrons charged?
Protons: Positive
Neutrons: No charge/ Neutral
Electrons: Negative
What are the horizontal rows of the periodic table called?
What was J.J. Thomson's model called?
The plum pudding model
Most elements are which of the following: metals, nonmetals, or metalloids?
Metals
Atoms of the same element have different numbers of neutrons in their nucleus is called what?
Isotopes
The electrons on the outermost shell is called what?
Groups of elements with similar properties on the periodic table are called what?
Families
Who discovered there were electrons in the atom?
J.J. Thomson
True or false? Alkali Metals are reactive.
True
True or false? Isotopes have the same number of protons and electrons, but different numbers of neutrons.
True
Which 2 particles make up an atoms mass?
Protons and Neutrons
What do periods tell us about an element?
Their energy level (how many shells)
Who discovered there is a nucleus in the atom? What experiment did he do?
Neither metals nor nonmetals, but have properties of both are called __________.
Metalloids
If I add one neutron to the nucleus of an atom do I have the same element?
Yes - it is an isotope
How many electrons can the 1st, 2nd, and 3rd shells/energy levels hold?
2, 8, 18
What do groups tell us about an element?
How many valence electrons
Who thought the atom was a small, dense ball?
John Dalton
What are the most stable gasses of the periodic table called?
Noble Gasses
In Carbon-14 what does the number 14 represent?
Atomic Mass
How many known elements are there?
118
What are the vertical columns of the periodic table called?
Groups
Who created the periodic table and why was it so significant?
Mendeleev - he left spaces for undiscovered elements
What are the 3 ways elements are classified on the periodic table?
metal, nonmetal, metalloid
C-14 has 6 protons. How many electrons and how many neutrons does C-14 have?
6 electrons and 8 neutrons