5 Boron H He Li Be [B ]C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr +--------------------+ | 5 ____ | | | __ ) | | | _ \ | | | |_) | | | |____/ | | | | Boron | | 10.81 u | +--------------------+ Electron Configuration: [He]2s2 2p1 Electronegativity: 2.04 Atomic Radius: 192 pm Ionization Energy: 8.298 eV Electron Affinity: 0.277 eV Oxidation States: 3 Standard State: Solid Melting Point: 2348 K Boiling Point: 4273 K Density: 2.37 g/cm3 Family: Metalloid Year Discovered: 1808 Number of Neutrons: 6 Number of Protons: 5 Number of Electrons: 5 Number of Valence: 3 Valency: 3 Group: 13 Period: 2 Shell: p-shell Specific Heat: 1.026 J/g K Radioactive: 0 Occurrence: Natural Source: Cosmic ray collision