Who organized the first periodic table by chemical properties and atomic mass in 1871?
Dmitri Mendeleev
What is the weighted average mass of all isotopes of an element?
Atomic mass

What is represented by the orange column on the right?
What is the greatest electronegativity and most reactive nonmetal?
Fluorine :)))
A vertical column in the periodic table is called?
Groups :max_bytes(150000):strip_icc()/chemcat_argon-58b5ae0f5f9b586046ad469b.jpg)
Who determined the atomic number of elements?
Henery Moseley
What is the measure of the tendency of an atom to attract a bonding pair of electrons?
Electronegativity

What does the red column represent?
Alkali Metals

What type of electronegativity trend is represented by the arrows?
Ionization energy
A horizontal row in the periodic table is called a?
Period!!!!!
Define - "When the elements are arranged in order of increasing atomic number, there are patterns in their chemical and physical properties."
Periodic Law
What is the inner electrons barrier called when the outer electrons are shielded from the pulling of the nucleus?
Shielding Effect

What is located in the "stair steps"?
Metaloids

What id increasing with the arrows?
Atomic Size
How is the modern periodic table arranged?
By atomic number
who grouped together elements based on properties? (gases, non-metals, and metals)
Lavoisier
What is it called when the periodic table shows patterns and trends?
Periodic 

What is represented by the two horizontal rows at the bottom of the table?
Inner Transition Metals
True or False?
Small atoms = high ionization energy

What group has the outermost S and P full?
Noble Gases

who incorporated transition metals into the periodic table?
Meyer
What is the measurement of the size of an atom from the center of the nucleus to the edge of the electron cloud?
Atomic Radius

What is represented by the light blue section in the center of the table?
Transition Metals
What is the energy required to remove an electron from a gaseous atom?
Ionization energy
What group has the outermost S and nearby F containing electrons?
Inner Transition Metals