If the center atom has four single bonds around it, what type of molecular geometry is present

Use the periodic table and your knowledge of isotopes to complete these statements. when polonium-210 emits an alpha particle, the child isotope has an atomic mass of 1-131 undergoes beta-minus decay. the chemical symbol for the new element is fluorine-18 undergoes beta-plus decay. the child isotope has an atomic mass of done intro donne