The atomic model and ionising radiation

Democritus is attributed to stating the atom as:

• Invincible

• Invisible

• Indecipherable

• Indivisible

Dalton revisited Democritus's model of the atom. Which of the following is NOT Dalton's version of the atom?

• Elements are made of extremely small particles called atoms

• Atoms of a given element are identical in size, mass and other properties; atoms of different elements differ in size, mass and other properties.

• Atoms cannot be subdivided, created or destroyed.

• Atoms are made of electrons orbiting a compact positively charged nucleus

This question is about the properties of particles that make up an atom. Which of the following statement is correct?

• Proton is positively charged particles smaller than the electron

• Electron is a negatively charged particle found in the atom

• Neutron is a neutral particles orbiting the nucleus of an atom

• Electrons are only found orbiting the nucleus of an atom

J J Thompson discovered the electron. Which of following is approximate mass of electron?

• 1/20 relative mass of proton

• 1/200 relative mass of proton

• 1/2000 relative mass of proton

• 1/20000 relative mass of proton

The atomic number of an atom is denoted by which symbol

• X

• N

• Z

• A

Atomic mass (also known as mass weight or mass number) of an atom is denoted by which symbol?

• Y

• N

• Z

• A

The model of the atom proposed by J J Thompson was called the Plum Pudding Model. Which of following is best description of this model?

• the pudding represented the positive charge distributed over the atom, the plums represented the random distribution of negative charge of electron

• the pudding represented the negative charge distributed over the atom, the plums represented the random distribution of positive

Rutherford explored the nature of the atom. He bombarded alpha particles on a thin gold leaf and observed the angle of deflections. What is an alpha particle?

• alpha particle is a hydrogen nucleus

• alpha particle is a helium nucleus

• alpha particle is a fast moving electron

• alpha particle is an electromagnetic wave

In Rutherford's alpha scattering experiment, why was gold used?

• gold is does not tarnish in air

• gold can be hammered into thin foil

• gold does not react with alpha particles

• gold is a good conductor of electric current

Which of the following can be concluded from Rutherford's experiment

• atom is mostly empty space

• atom has a dense nucleus

• atom has a dense positive nucleus

• atom has a dense, compact positive nucleus