|By 18__, chemists had isolated and named __ different elements.|
Mendeleev left _____ gaps on the periodic table, because these elements had been discovered yet:
1.) _ _ _ _ _ _ _
2.) _ _ _ _ _ _ _ _
3.) _ _ _ _ _ _ _ _ _
|How did Henry Moseley improve Mendeleev’s periodic table?|
|He arranged the elements in order of atomic number rather than atomic mass. This made it clear how many elements were still undiscovered.|
|Rows on the periodic table are labeled _ – _.|
|Period- row of elements in the periodic table whose properties change gradually and predictably.|
|Each groups contains elements that have similar physical or chemical properties (columns).|
;Eight groups that include metals, metalloids and nonmetals.
This section includes groups 1 ; 2, 13-18.
|Elements in groups 3-12 that are all metals.|
An element that
– has luster
– is a good conductor of heat ; electricity
– is malleable
– is ductile
|Gases or brittle solids at room temperature that are poor conductors of heat and electricity.|
|An element that shares some properties with metals, and some with nonmetals.|
|How are alkali metals different from alkaline earth metals?|
|Alkali metals are silvery solids with low densities and melting points, while alkaline earth metals are denser and harder, and have higher melting points than alkali metals in their same period.|
Doesn’t conduct electricity as well as a metal, but does conduct electricity better than a nonmetal.
Think of silicon in computer chips.
|Group 17’s family name, which means “salt formers.”|
|In what way did Dmitri Mendeleev contribute to the periodic table?|
|He arranged the first official periodic table in 1869. He arranged the elements in order of increasing atomic mass.|
|the ability to reflect light|
|What group are the alkali metals in, and what are some of their characteristics?|
Alkali metals are silvery solids with low densities and melting points.
|What group are the alkaline earth metals in, and what are some of their characteristics?|
They are denser, harder and have higher melting points than alkali metals in the same period.
|Groups 3-12 are _ _ _ _ _ _ _ _ _ _ metals.|
|Group 13 is the Boron family, which are all metals- except for boron, which is a metalloid.|
|Group 14 is the Carbon Group, which contains a nonmetal, two metalloids and two metals.|
|Group 15 is the Nitrogen Group, and it has all metal-groups covered, just like Group 14.|
|Group 16 is the _ _ _ _ _ _ Family. It has _ _ _ _ _ nonmetals, and _ _ _ metals.|
|What does the word “halogens” mean?|
|Group 17 is the _ _ _ _ _ _ _ Group. They are all nonmetals, except for _ _ _ _ _ _ _ _, which is a radioactive _ _ _ _ _ _ _ _ _.|
|Group 18 is the Noble Gases, all six are nonmetals and have low reactivity. They rarely combine with other elements.|
|a substance that can make something happen faster but is not changed itself.|
|What elements are in the Iron Triad?|
Iron, Cobalt and Nickel.
They have very similar properties.
|First series of inner transition elements which ranges from cerium to lutetium.|
|Second series of inner transition elements that ranges from thorium to lawrencium.|
|Elements made in laboratories; do not exist naturally.|