(WILL MARK BRANLIEST) Based on the placement on the Periodic Table, what set of elements have the same number of energy levels?

Hydrogen, helium, and lithium

Boron, silicon, and arsenic

Carbon, nitrogen, and oxygen

Titanium, zirconium, and hafnium

If a clock aboard a space ship traveling at 0.900 c of the speed of light relative to earth chimes once at the beginning of the hour and again when it reads one hour later, how much time would an observer on earth say elapsed between the two chimes?

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The vapour pressure of benzene is 53.3 kpa at 60.6 °c, but it fell to 51.5 kpa when 19.0 g of a non-volatile organic compound was dissolved in 500 g of benzene. calculate the molar mass of the compound.