Chemistry module 2 - part 1

What evidence from J.J. Thomson's experiments with the cathode ray led to the plum pudding model of the atom?

• The beam was attracted to a positive charge and repelled by a negative charge, showing that atoms contain small, negatively charged particles.

• The beam was attracted to a negative charge and repelled by a positive charge, showing that atoms contain small, positively charged particles.

• The beam was positively charged and had significant mass, showing that atoms have a positive, dense nucleus.

• The beam was neutral and had significant mass, showing that atoms contain neutral particles in the nucleus.

Match the scientist to his contribution to the atomic theory.

Thomson

• Electrons

• Nucleus

• Electron energy levels

Match the scientist to his contribution to the atomic theory.

Rutherford

• Electrons

• Nucleus

• Electron energy levels

Match the scientist to his contribution to the atomic theory.

Bohr

• Electrons

• Nucleus

• Electron energy levels

What is true when an ion is formed?

• The atom loses one or more neutrons.

• The atom loses one or more protons.

• There is an unequal number of electrons and protons.

• There is an unequal number of electrons and neutrons.

What is true of electrons?

• They are negatively charged and located inside the nucleus.

• They are negatively charged and located outside the nucleus.

• They are positively charged and located outside the nucleus.

• They are positively charged and located inside the nucleus.

In the 1800s, one of the statements in John Dalton's atomic theory was that atoms are indivisible. Later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. What happened to the indivisible atom part of Dalton's atomic theory, and why?

• The entire theory was discarded because Dalton's scientific reputation was ruined once new evidence invalidated part of his theory.

• The indivisible atom part of the theory was discarded because consensus of data must exist for theories to be valid.

• The theory remained unchanged because Dalton was correct regarding all other statements within the accepted scientific theory.

• The theory remained unchanged because new data is discarded if it doesn't fit within the accepted theory.

Which hypothesis of Thomson's atomic model was later found to be not true by Niels Bohr and why?

• Thomson hypothesized that an atom was a sphere with negative electrons in it and positive protons around it however it was discovered to be the other way round as negative electrons around the center where positive charged protons are.

• Done

Energy has both wavelike and particle-like properties, but electrons have only particle-like properties.

• True

• False

Which type of electromagnetic radiation has a longer wavelength than visible light?

• Gamma rays

• Infrared radiation

• Ultraviolet radiation

• X‒rays