ATOMS, MOLECULES AND IONS 2

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Why did Thomson propose that the particles he observed must be negatively charged?

Because they were heavier than atoms.

Because they were distinguishable based on the source material.

Because they attracted negative charges and repelled positive charges.

Because they attracted positive charges and repelled negative charges. (correct)

How did Millikan determine the charge on individual oil droplets in his 'oil drop' experiments?

By using X-rays to charge the droplets.

By adjusting the electric field strength and making calculations. (correct)

By measuring the mass of the droplets.

By adjusting the temperature of the apparatus.

What fundamental charge value did Millikan conclude from his oil drop experiments?

1.6 × 10^-19 C (correct)

2.0 × 10^19 C

-1.6 × 10^-19 C

-1.0 × 10^-19 C

According to Thomson, what model of atoms proposed a positively charged mass with an equal amount of negative charge in the form of embedded electrons?

'Plum pudding' model Signup and view all the answers

What type of particles did Rutherford use in his experiment with gold foil?

Alpha particles Signup and view all the answers

What was the main observation made by Rutherford and his colleagues when they directed alpha particles at gold foil?

Most particles passed through without being deflected. Signup and view all the answers

What did English physicist J.J. Thomson discover using a cathode ray tube?

Cathode rays are deflected towards positive charge and away from negative charge. Signup and view all the answers

What type of beam appeared when high voltage was applied across the electrodes in the cathode ray tube?

Cathode ray Signup and view all the answers

In Thomson's experiments, how was the cathode ray deflected in the presence of an applied magnetic field?

Simultaneously along with the magnetic field Signup and view all the answers

What allowed Thomson to calculate the charge-to-mass ratio of the cathode ray particles?

Extent of deflection and magnetic field strength Signup and view all the answers

What was significant about the beam produced in the cathode ray tube when different metals were used for the electrodes?

The beam had identical properties. Signup and view all the answers

What were scientists interested in investigating in the late 1800s related to atoms?

Questions about what atoms are composed of Signup and view all the answers

What did Rutherford deduce about the structure of the atom from his experiment with alpha particles?

Atoms consist of mostly empty space with a small, positively charged nucleus. Signup and view all the answers

Why did Rutherford's alpha particles get deflected when passing through the gold foil?

They encountered other positively charged particles, causing repulsion. Signup and view all the answers

What did Frederick Soddy discover that led to the concept of isotopes?

Atoms can have types with different masses but identical chemical properties. Signup and view all the answers

What component of an atom did James Chadwick discover in 1932?

Neutrons Signup and view all the answers

Why were the nuclei of other elements found to contain isotopes?

Due to different numbers of neutrons but the same number of protons in different isotopes. Signup and view all the answers

What did Rutherford propose was at the center of each atom based on his experiments?

A small, positively charged nucleus. Signup and view all the answers

Why did Rutherford compare the deflection of alpha particles to firing a shell at tissue paper?

To highlight the unexpected and extreme nature of the deflections. Signup and view all the answers

What was the significance of discovering isotopes in early 1900s chemistry?

It revealed that atoms have variable masses but fixed chemical properties. Signup and view all the answers

What did Thomson propose about the particles he observed based on their interaction with charges?

They must be negatively charged. Signup and view all the answers

How did Millikan determine the charge on individual oil droplets in his experiments?

By adjusting the electric field strength and making careful measurements. Signup and view all the answers

What did George Stoney coin the term 'electron' from?

From 'electric ion.' Signup and view all the answers

What model of atoms did Thomson propose in 1904?

'Plum pudding' model. Signup and view all the answers

What was the next major development in understanding the atom after Thomson's 'plum pudding' model?

'Rutherford' model. Signup and view all the answers

What type of beam appeared between the electrodes in J.J. Thomson's cathode ray tube experiments?

A visible beam called a cathode ray deflected by electric and magnetic fields Signup and view all the answers

How did the cathode ray particles behave when different metals were used for the electrodes in Thomson's experiments?

They maintained identical properties Signup and view all the answers

What allowed J.J. Thomson to calculate the charge-to-mass ratio of the cathode ray particles?

The extent of deflection and magnetic field strength Signup and view all the answers

What did J.J. Thomson observe about the behavior of the cathode ray in relation to positive and negative charges?

It was attracted to the positive charge and repelled by the negative charge Signup and view all the answers

Which aspect of J.J. Thomson's experiments led to the most significant discovery about matter in the late 1800s?

Producing a visible beam between electrodes Signup and view all the answers

What did Rutherford deduce from the fact that most alpha particles passed through gold atoms undeflected?

The alpha particles must have encountered a positive charge. Signup and view all the answers

What conclusion did Rutherford draw about the volume occupied by an atom from his experiments with alpha particles?

It is mostly empty space. Signup and view all the answers

What led Frederick Soddy to realize the existence of isotopes?

Different atomic masses of chemically identical elements. Signup and view all the answers

What did James Chadwick's discovery of neutrons help explain about isotopes?

Their differing mass numbers. Signup and view all the answers

How did Rutherford's model propose an atom is structured?

A positively charged nucleus orbited by electrons. Signup and view all the answers

What led Rutherford to propose a model in which an atom consists of a very small, positively charged nucleus surrounded by negatively charged electrons?

Encountering deflections when alpha particles hit positive charges in the gold foil Signup and view all the answers

What crucial discovery led Frederick Soddy to realize that an element could have types of atoms with different masses but that were chemically indistinguishable?

Isotopes Signup and view all the answers

What subatomic particle did James Chadwick discover in 1932 that helped explain the existence of isotopes?