## VALENCES


Default number of bonds to each element, used by [Builder.add_hydrogens](Builder.add_hydrogens.md#tetramol.Builder.add_hydrogens).


`VALENCES={`\
`    `<span class="st">`"H": 1,`\
`    ``"B"``: 3,`\
`    ``"C"``: 4,`\
`    ``"N"``: 3,`\
`    ``"O"``: 2,`\
`    ``"F"``: 1,`\
`    ``"Si"``: 4,`\
`    ``"P"``: 3,`\
`    ``"S"``: 2,`\
`    ``"Cl"``: 1,`\
`    ``"Br"``: 1,`\
`    ``"I"``: 1,`\
`}`</span>