What is the daughter nucleus (nuclide) produced when Sr90Sr90 undergoes beta decay by emitting an electron

The difference between the atomic number of an element and the element’s atomic mass is the number of ions.

Match term definition ellipse a) diagonal cross section of a cylinder circle b) diagonal cross section through the widest part of a sphere sphere c) cross section parallel to the base of a cone great circle d) shape created when a semi-circle is rotated around the y-axis triangle e) perpendicular cross section of a cone

The element that has the greatest electronegativity is