Periodic Table Basics
What determines the order of elements in the periodic table?
Number of protons
What do all elements in Group 1 have in common?
They all have one valence electron and are alkali metals
What state of matter are most metals at room temperature?
solids
What part of the atom contains protons and neutrons?
nucleus
Which group of metals is the most reactive?
Alkali metals (Group 1)
What is the vertical column on the periodic table called?
A group
What is another name for Group 17 elements?
Halogens
Which group of elements is brittle and poor at conducting heat?
nonmetals
How many electrons can the first shell of an atom hold?
2
What property did Mendeleev use to arrange elements in his first periodic table?
atomic mass
How does atomic number change as you move from left to right across a period?
it increases
What do all elements in Group 18 (noble gases) have in common?
They have full outer electron shells and are non-reactive
What type of element has properties of both metals and nonmetals?
metalloids
What is the charge of a neutron?
neutral
Why did Mendeleev leave gaps in his periodic table?
He predicted undiscovered elements
What do elements in the same period have in common?
They have the same number of electron shells
Which group of elements is located in the center of the periodic table, between Groups 3 and 12?
Transition Metals
Which metal is commonly found in batteries and is highly reactive?
Lithium (an alkali metal)
What happens to an atom when it loses or gains electrons?
it becomes and ion
Why do elements in Group 17 (halogens) tend to gain an electron in reactions?
To complete their outer electron shell and become more stable
Which scientist is credited with creating the first periodic table?
Dmitri Mendeleev
What characteristic do the elements in Group 2 (alkaline-earth metals) share?
They have two valence electrons and are reactive
What is a semiconductor, and why is it important?
A material that conducts electricity under certain conditions, important in electronics
What do we call the outermost electrons of an atom?
valence electrons
What is the periodic law?
The properties of elements repeat in a periodic pattern when arranged by increasing atomic number