As you move from left to right across a period in the periodic table, atomic radius generally:

A neutral atom: Contains 20 neutrons. Has 18 electrons. Belongs to the noble gases. Has a lower mass number than another isotope of the same element. Which statement must be true?

A laboratory bench has a length of {L} m. Convert this length to centimeters.  Enter your answer as a number only.

A sealed container recovered from a laboratory contains a colorless gas. Scientists make the following observations: The gas is a pure substance. Spectroscopic analysis shows a single set of emission lines. Every atom in the sample contains 18 protons. Approximately 60% of the atoms contain 22 neutrons, while 40% contain 20 neutrons. The gas is extremely unreactive under normal conditions. Repeated mass measurements of the sample are highly precise but consistently 2% lower than the accepted value. Which conclusion is most strongly supported by all of the evidence?

Atoms of same element with different numbers of neutrons are called:

The visible hydrogen spectrum has a blue colored line at 487 nm. Assume that nf = 2. In the Rydberg equation the value of ni for this blue line is _________.    1nm = 10^-9 m      

Methanol has a normal boiling point of 64.6°C and a heat of vaporization, ΔHvap, of 35.2 kJ/mol.  What is the vapor pressure(torr) of methanol at 12.0°C ?

Carbon disulfide has a vapor pressure of 363 torr at 25°C and a normal boiling point of 46.3°C.  Find ΔHvap (kJ/mol) for carbon disulfide.  

The correct name of this chemical compound, CaSO4· 2 H2O

The abbreviation for the left ear is: