Question

The table below gives the group number of five elements:
Element: Caesium(Cs)(Group number:1)--Barium(Ba)(Group number:2)--Gallium(Ga)(Group number:3)--Selenium(Se)(Group number:6)--Astatine(At)(Group number:7)
a) Determine the chemical formula of gallium oxide.
b) Explain whether caesium will exist as a free element in nature.
c) Write the chemical formula and draw the election diagram for the compound formed between barium and astatine. (Show electrons on outermost shells only)
d) Write the chemical formula and draw the electron diagram for the compound formed between hydrogen and selenium. (Show electrons in outermost shells only)

Answer 1

Answer:

c

The concept that the embryos of higher order organisms progress through successive stages in which they resemble lower level forms is called recapitulation.