Answer:
1.Hydrogen: 1s1 2 - Helium: 1s2
45 – Rhodium: [Kr], 5s2, 4d7 46 – Palladium: [Kr], 5s2, 4d8
47 – Silver: [Kr], 5s2, 4d9 48 – Cadmium: [Kr], 5s2, 4d10
49 – Indium: [Kr], 5s2, 4d10, 5p1 50 – Tin: [Kr], 5s2, 4d10, 5p2
Thus 43 electrons, so the neutral atom has atomic number 43. Look at a periodic table and you see that this element is technetium.
Element Atomic Number Element Symbol Element Electron Configuration
45 Rh [Kr] 4d8 5s1
46 Pd [Kr] 4d10
47 Ag [Kr] 4d10 5s1
48 Cd [Kr] 4d10 5s2
