Mendeleev
Mendeleev arranged the known chemical elements in his table according to increasing
What is mass
This is a horizontal line of elements on the table based on increasing atomic mass
What is a period
These are the most reactive metals on the periodic table
What are the Alkali metals or group 1a
The number of each a group element represents this.
What are the number of valence electrons.
Alkali metals get more reactive as this way in the group.
What is down
Mendeleev gave this name to an undiscovered element he predicted would have similar properties to those of aluminum.
What is Eka-aluminum
This is a vertical line of elements placed based on the elements common properties.
What is a group.
These are the most reactive nonmetals.
What are the halogens or group 7a.
The weighted average of that elements isotopes as they are found in nature.
Elements in this group are placed there based on how they react with this.
What is water.
These are the three elements that Mendeleev left spaces for in his table that were later found.
What are Gallium, Scandium and Germanium
This is the weighted average of the masses of an elements isotopes.
What is atomic mass.
This group on the periodic table can have a charge of +4 or -4.
What is the carbon family.
Reactive elements are usually found in nature only as these.
What are compounds.
These elements emit different colors of light when electric current is exposed to them.
What are Noble Gasses
Mendeleev published his table here first.
What is a chemistry textbook he was writing.
This is one-twelfth of the mass of a carbon-12 atom.
What is an AMU
metals that change color when exposed to air do so because of this.
What is their high reactivity.
These can contain any of the different types of noble gases.
What are neon lights
At room temperature there are no metals that are this
What are gasses
Mendeleev created his table of elements without believing that these existed.
What are atoms
Like Aluminum this element has a very low melting point.
What is gallium
From left to right across the table metals become _____________ and nonmetals become
What is less reactive and more reactive
These two elements from the same group are found in fertilizers.
What are nitrogen and phosphorous.
The numbers of valence electrons an element has determines this.
What is reactivity.