SNC1W1 - Chemistry Lessons 5-8 Review

What is the relative mass of an electron compared to a proton?

• Approximately 1/2000

• Approximately 1

• Approximately 2000

• Approximately 0

Answer explanation

The mass of an electron is approximately 1/2000 that of a proton. This means that while electrons are much lighter than protons, they still have a measurable mass, making the correct choice approximately 1/2000.

Which subatomic particle is located in the nucleus and has no charge?

• Proton

• Neutron

• Electron

• Positron

Answer explanation

The neutron is a subatomic particle found in the nucleus of an atom and carries no electric charge, making it neutral. In contrast, protons are positively charged, electrons are negatively charged, and positrons are the antimatter counterparts of electrons.

How does the position of an element in the periodic table relate to its atomic number?

• The atomic number increases from right to left.

• The atomic number decreases from top to bottom.

• The atomic number increases from left to right.

• The atomic number is the same for all elements in a group.

Answer explanation

The atomic number, which represents the number of protons in an element's nucleus, increases from left to right across a period in the periodic table. This means that as you move right, elements have higher atomic numbers.

Which of the following elements is likely to have similar chemical properties to chlorine?

• Sodium

• Argon

• Fluorine

• Oxygen

Answer explanation

Fluorine is in the same group (Group 17) as chlorine on the periodic table, which means it shares similar chemical properties, such as reactivity and the ability to form similar compounds.

Which atomic model first introduced the concept of electron orbits?

• Dalton's model

• Thomson's model

• Rutherford's model

• Bohr's model

Answer explanation

Bohr's model, introduced in 1913, was the first to propose that electrons travel in specific orbits around the nucleus, quantizing their energy levels. This was a significant advancement over previous models.

What was a key piece of experimental evidence that led to the development of the Rutherford model of the atom?

• The discovery of the electron

• The gold foil experiment

• The discovery of isotopes

• The photoelectric effect

Answer explanation

The gold foil experiment conducted by Rutherford revealed that atoms have a small, dense nucleus, leading to the development of the Rutherford model. This experiment showed that most of the atom is empty space, contradicting the previous plum pudding model.

What is the charge of an electron?

• Positive

• Negative

• Neutral

• Variable

Answer explanation

The charge of an electron is negative. This fundamental property distinguishes electrons from protons, which have a positive charge, and neutrons, which are neutral.

Which group in the periodic table contains the noble gases?

• Group 1

• Group 2

• Group 17

• Group 18

Answer explanation

The noble gases are found in Group 18 of the periodic table. This group includes elements like helium, neon, and argon, which are known for their lack of reactivity due to having a full valence shell.

Which atomic model is known for introducing the concept of a nucleus?

• Dalton's model

• Thomson's model

• Rutherford's model

• Bohr's model

Answer explanation

Rutherford's model, introduced in 1911, is known for proposing the existence of a nucleus at the center of the atom, surrounded by electrons. This was a significant advancement over previous models, which did not include a nucleus.

What is the primary factor that determines the chemical reactivity of an element?

• Density

• Number of valence electrons

• Number of neutrons

• Atomic mass

Answer explanation

The primary factor that determines an element's chemical reactivity is the number of valence electrons. These electrons are involved in bonding and reactions, influencing how an element interacts with others.