No stable isotope of an element has mass no 18, although unstable isotopes of fluorine and oxygen have mass no 18, 8O18 and 9F18
Argon! Noble Gas!
Atomic number 18 is Argon (Ar).
argon
Argon (Ar, element number 18) is the last element in the third period of the periodic table.
group 18
Helium is located on the group 18 and period 1 on the modern periodic table.
Sodium is the eleventh element on the periodic table.
Noble gases are found in group 18 of the periodic table.
periodic table is classified into groups and periods.There are 18 groups and 7 periods in periodic table.
Argon.
The periodic table of Mendeleev has 18 groups and 7 periods.
argon
Argon (Ar, element number 18) is the last element in the third period of the periodic table.
group 18
group 18
Radium (Ra) # 88th element in the periodic table.
Helium is located on the group 18 and period 1 on the modern periodic table.
Because Palladium is an element (it cannot be broken down into other substances) and the periodic table is a table of all of the elements we know of.
Argon has atomic number 18 and is the third element in group 18 of the periodic table