Atomic Structure
The subatomic particles in the nucleus of an atom
protons and neutrons
Periods
The elements that are gases and have 7 valence electrons
Halogens
The scientist who is credited with developing an orderly way to classify and organize elements
Dimitri Mendeleev
Mendeleev
As you move down groups, the atomic radius of elements: increase, decrease, or stay the same.
increase
Negatively charged particles far outside the nucleus
Electrons
The name for the 18 columns on the periodic table
groups
The family of metals that all have 2 valence electrons
Alkaline Earth metals
The original periodic table was structured based on the order of ______________ _______________.
Atomic masses.
decreases
In a neutrally charged atom, the number of ____________ and ____________ are equal to each other
protons and electrons
An element is in Group 9, period 4. What is it?
Cobalt
Gases with 8 valence electrons, they are very stable
Noble Gases
The modern periodic table orders the elements based on their ______________ _______________.
Atomic Numbers
The tendency of an atom to attract electrons to itself
Electronegativity
An element has 56 protons. What is it?
Barium
Which type of element (metal, non-metal or metalloid) is sodium?
metal
Elements that are dull, vary in colors and are brittle
non-metals
The element that breaks the rule about metals being left of the staircase
hydrogen
As you move down groups on the periodic table, the electronegativity ________________ as atomic radius increases.
decreases
The number of neutrons in an atom of silver
39
Which type of element (metal, non-metal or metalloid) is Arsenic?
Metalloid
Elements that are thermally and electrically conductive, ductile, and malleable - make up 80% of the periodic table
metals
The element that breaks the rule about the valence electron number being the same as the group number (group number minus 10 for 13-18)
Helium
The most reactive elements on the periodic table are in this family:
Alkali Metals