Ineed the answers to my science questions

What’s the scientific notation for the number 6,840,000,000

Which reason best explains why metals are malleable? a)because they have delocalized electrons b)because they have localized electrons c)because they have ionic bonds d)because they have rigid bonds

Percent ionization for a weak acid (ha) is determined by the following formula: percent ionization=[ha] ionized[ha] initial×100%for strong acids, ionization is nearly complete (100%) at most concentrations. however, for weak acids, the percent ionization changes significantly with concentration. the more diluted the acid is, the greater percent ionization. a certain weak acid, ha, has a ka value of 9.4×10? 7.part acalculate the percent ionization of ha in a 0.10 m solution. part bcalculate the percent ionization of ha in a 0.010 m solution