Atomic Theory Pt. 2

The atomic number for Oxygen is 8, so

• there are 8 protons in the atom
• the atomic mass is less than 8
• the mass of the atom is 8
• the atom is decaying

Tags

NGSS.MS-PS1-1

Which scientist saw the atom as a positively charged sphere with negative particles (electrons) embedded within?

• J.J. Thomson
• Niels Bohr
• John Dalton
• Ernest Rutherford

Tags

NGSS.MS-PS1-1

Which scientist proposed a model of the atom in which the electrons are orbiting at different levels?

• Niels Bohr
• James Chadwick
• John Dalton
• Ernest Rutherford

J.J. Thomson's model of the atom is given this name because he believed that electrons were spread randomly throughout a positive sphere.

• plum pudding model
• orbital model
• Thomson's model
• plasma model

Which scientist proposed a model of the atom in which the individual atoms were thought of as tiny solids like balls or marbles?

• John Dalton
• James Chadwick
• Ernest Rutherford
• J.J. Thomson

Which statement is true according to current thinking?

• An atom is mostly empty space.
• An atom is a collection of particles, so tightly packed that there is little empty space.
• The atomic nucleus is very mobile, and moves around inside a cloud of electrons.
• The size of atoms changes over time, pulsating from large to small to large again.

Which of the following correctly describes the electron cloud model?

• Electrons do not follow fixed orbits, but are found more frequently in areas around the nucleus.
• Electrons are found in fixed orbitals around a positive nucleus.
• All of an atom's mass is concentrated in the electron cloud around the nucleus.
• Electrons are evenly embedded throughout a positively charged sphere.

According to modern atomic theory, electrons are found ___.

• occupying unspecified regions around the nucleus, based on how much energy each electron has
• in totally random and varying orbits around the nucleus
• in fixed orbits at well-defined distances from the nucleus
• closely attached to the nucleus

Rutherford discovered that atoms have a very tiny, positively charged center where most of the mass is found. His model was nicknamed the ___.

• Nuclear Model
• Plum Pudding Model
• Electron Cloud Model
• Billiard Ball

Who discovered a particle in the nucleus with no charge called the neutron?

• Chadwick
• Bohr
• Rutherford
• Dalton