How do you calculate the number of valence electrons in an atom?

This large tectonic plate is bounded on three sides by whats know as the ring of fire. what is the name of this tectonic plate? a) pacific plate b) eurasian plate c) north american plate d) indo- australian plate plz it's science but there's no option for science so i picked chemistry

Which step in naming unsaturated hydrocarbons is used for alkenes but not alkynes

Determine the reaction and balance the following equations urgent due in the morning