Organizing the Elements
Who first arrange elements in order of increasing mass and group by properties
Mendeleev
One twelfth of the mass of a carbon-12 atom is used to define this
Atomic mass unit
The tendency of an element to react is closely related to this factor.
the number of valence electrons in the element.
To keep reactive elements from reacting they are often store in this
Noble Gasses or oil.
These type of light may actually contain any noble gas.
Neon lights
This was the first person to group elements based on whether they are metals, nonmetals, gases, and earths
Antione Lavoisier
At room temperature metals are all either solids or this
Liquids
Elements in the nitrogen family have this many valence electrons.
Five
This element in the Alkali Metals is least likely to react.
Hydrogen
Hydrogen is in the Alkali metals group because it has this
One valence electron
On each card Mendeleev wrote which items
Elements name
elements mass
elements properties
Most of these are malleable ductile and good conductors of heat and electricity.
Metals
Noble gases are not likely to react for this reason.
Their outermost energy level is filled with electrons.
When Mendeleev organized the elements he arranged them by mass placing the elements with similar properties here.
Same column or group.
Reactive elements like alkali metals and halogens are found in nature on as this.
Compounds
Which element did Mendeleev name eka-aluminum?
Gallium
Elements in group 7A are also called this.
Halogens
This element in group 7 elements is least reactive
Astatine
Mendeleev believed that like aluminum, eke aluminum would have a low this
Melting point
Fertilizers often contain these two elements from group 5A
Nitrogen and phosphorous
This is the weighted average of the masses of an elements isotopes.
Atomic Mass
Atoms most likely to react tend to have
one or seven valence electrons
These elements emit different colors of light when an electric current is applied to them.
Noble Gasses
Other than Alkali metals these are also very reactive metals.
Alkaline Earth Metals
Moving from left to right across a period elements get less __________ and more _______________ in their properties
metallic , non metallic