Chemistry Semester Exam

Experimental evidence was a critical factor in developing the atomic model. What is an example of evidence that helped develop the Dalton atomic model?

• The path of cathode rays is affected by a magnet. 

• Alpha particles are deflected at large angles.

• Elements give off specific colors of light when heated in a flame.

• Elements combine in simple whole-number ratios to form compounds.

The periodic table

• permits the properties of an element to be predicted before the element is discovered.

• will be completed with element 118.

• has been of little use to chemists since the early 1900s.

• was completed with the discovery of the noble gases.

Rutherford expected alpha particles to travel almost straight through a target of gold foil. Which concept was not supported by his experimental results and research?

• Millikan’s measurement of electrical charge

• Thomson’s plum pudding model of the atom

• the existence of electrons as particles

• the planetary model of the atom

An atom has an atomic number of 26 and a mass number of 56. What is the composition of the atom?

• 26 protons, 56 neutrons, 26 electrons

• 30 protons, 26 neutrons, 30 electrons

• 26 protons, 30 neutrons, 26 electrons

• 30 protons, 30 neutrons, 26 electrons

The mass of the ashes left from burning a log is less than the mass of the log. Which explains why this is not a violation of the law of conservation of mass?

• Some of the mass of the log is converted into energy.

• The ashes are made of simpler compounds than were in the log.

• New lighter atoms are produced during combustion.

• Much of the mass of the log escapes as gases.

An atom has 23 protons and 28 neutrons. Which is the correct chemical symbol for this atom?

• ⁵¹₂₃V

• ¹²₆C

• ⁶⁴₂₉Cu

• ⁵²₂₄Cr

The following symbols represent isotopes of four fictitious elements, W, X, Y, and Z.

Which isotope contains the most neutrons?

• Y

• W

• Z

• X

What of the following isotopes have the same number of neutrons?

silver-108, palladium-107, cadmium-109, indium-108, rhodium-108

• silver-108, palladium-107, cadmium-109, indium-108

• silver-108, indium-108, rhodium-108

• silver-108, palladium-107, cadmium-109, indium-108, rhodium-106

• silver-108, palladium-107, cadmium-109

A lead atom contains 82 protons and 125 neutrons. Which is the correct notation for this isotope of lead?

• 
• 
• 
• 

What many electrons can a each p-orbital accommodate?

• 4

• 6

• 2

• 10