An atom has an atomic number of 13 and mass number of 27. In which group of the periodic table can the element be found?
Group III A
The element is Aluminum atomic number 13 and with a mass of 27 has 14 neutrons the most common and stable isotope of Aluminum
The stable element Neon has 10 electrons filling the second atomic shell. This leaves 3 valance electrons in the the third shell. Each valance electron moves the element over 1 group. So Aluminum is in group III A.