関連ワード:  what is the group in periodic table    what is the group number in periodic table    what is the main group in periodic table    what is the group 1 in periodic table    what is the zero group in periodic table    what is the group 3 in periodic table    what is down the group in periodic table    what is the first group in periodic table    what is the group 2 in periodic table    what is the group 7 in periodic table