History
What property are elements on the periodic table organized by?
Atomic number / number of protons
What are rows on the periodic table called?
periods
Most elements on the periodic table are: metals, nonmetals, or metalloids
metals
What element is the most electronegative?
Fluorine
What does periodic law state?
There is a periodic repetition of physical and chemical properties of elements when they are arranged in order of increasing atomic number.
What was the first periodic table arranged by?
Atomic mass
What are columns called on the periodic table?
Groups or families
What is the name of the most reactive metals?
Alkali Metals
What element has the largest atomic radius?
Francium
Who created the first periodic table?
Dimitri Mendeleev
What do elements in the same period have in common?
number of energy levels
What are the most reactive nonmetals?
Halogens
What happens to ionization energy as you move across the period?
Increases
Who first arranged the MODERN periodic table?
Henry Moseley
The number of valence electrons in group 17 elements is what?
7 valence electrons
Name two physical properties of metals.
Ductile, malleable, shiny, conductive, etc.
Which alkaline-earth metal is the most reactive?
Radium
What was one challenge with creating the first periodic table?
Undiscovered elements left gaps
Arrangement by atomic mass didn't fully match trends in properties
What element has 5 energy levels and 4 valence electrons?
Sn, Tin
This element does not belong to the family of elements that the rest of its group belongs to.
Hydrogen
Why does atomic radius decrease across the period?
More protons in nucleus = more positive charge
Attracts negative electrons and pulls them in closer