Rutherfordium

Rutherfordium is atom number 104 — every Rutherfordium atom has exactly 104 protons in its center, and that number is what makes it Rutherfordium and nothing else. Its symbol is Rf. At room temperature it is a solid.

Rutherfordium is a chemical element with symbol Rf and atomic number 104, named in honor of physicist Ernest Rutherford. It is a synthetic element (an element that can be created in a laboratory but is not found in nature) and radioactive; the most stable known isotope, 267Rf, has a half-life of approximately 1.3 hours. In the periodic table of the elements, it is a d - block element and the second of the fourth - row transition elements.

Summary from the source dataset, derived from Wikipedia (CC BY-SA 3.0) · original article

Rutherfordium sits in period 7, group 4 of the d-block. Its 104 electrons fill shells of 2, 8, 18, 32, 32, 10, 2 — written as [Rn] 5f14 6d2 7s2. Its electronegativity is — on the Pauling scale, and pulling the first electron off takes 580 kJ/mol. The outermost shell holds 2 electrons — the ones that do all the chemistry.

Full configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p6 6s2 4f14 5d10 6p6 7s2 5f14 6d2
Ionization energies (kJ/mol): 580
Electron affinity: — kJ/mol · Electronegativity (Pauling): —
Density: 23.2 g/cm³ · melts 2400 K · boils 5800 K

Values exactly as published — see where the data comes from.