An element that is a very reactive gas is most likely a member of
Most elements in the periodic chart are __.
Moseley rearranged the elements in Mendeleev's periodic table in terms of ___.
The element _____ is a metalloid.
are made of atoms with few electrons in their outer energy level
The Atomic mass of mercury is ___.
Each square on the periodic table includes an element's____.
name, chemical symbol, atomic number and atomic mass
The elements in a period on the periodic table become___.
less metallic moving from left to right
On the periodic table a column of elements is called_____.
a group or family
On the periodic table, a row of elements is called _____.
Why are halogons considered to be the most reactive group of nonmetals?
their atoms gain only one electron to have a complete outer level
Which of the following is the least reactive?
Elements in a family or group in the periodic table often share similar properties because____.
their atoms have the same number of electrons in their outer energy level
16. Atoms of most metallioids have _____ electrons in their outer energy level.
about a half complete set of
15. Atoms of one group of nonmetals, the noble gases, have ___ electrons in their outer energy level.
a complete set of
Atoms of most nonmetals, have ___ electrons in their outer energy level.
an almost complete set of
Which of the following metals is most reactive?
In the periodic table, elements are classified as ___ according to their properties.
metals, nonmetals, and metalloids
How many elements are in the first period of the periodic table