Answer:
In explanation
Explanation:
a. Selenium, atomic number 34
Argon is 18, adding the other electrons gives 34.
Other elements include: oxygen O , Sulphur S , Tellurium Te and Polonium Po
b. Hafnium, element 72
Xe is 54, adding the other electrons makes the total 72.
Other elements; Titanium Ti, Zirconium Zr, Rutherfordium Rf
c. Manganese, element 25
Other group members are Technetium Tc , Rhenium Re and Bohrium Bo
