1.2 The Nuclear Atoms

Question 1

Atoms

Answer 1

The fundamental building blocks of matter, but they are not indivisible.

Question 2

Components of atoms

Answer 2

• Protons
• Electrons
• Neutrons

Question 3

Nucleus

Answer 3

• The center of the atom
• A nucleus is a dense, positively charged core that contains protons and neutrons, collectively called nucleons.

Question 4

Protons

Answer 4

• These are positively charged particles with a relative charge of and a relative mass of 1.
• The number of protons in the nucleus determines the atomic number (Z), which defines the element.
• Charge = 1, mass = 1

Question 5

Neutrons

Answer 5

• These particles are neutral, with no charge, and have a relative mass of 1.
• Neutrons help to stabilize the nucleus by offsetting the repulsion between protons.
• The number of neutrons can vary between atoms of the same element, leading to isotopes.
• Charge = 0, mass = 1

Question 6

Electrons

Answer 6

• Are negatively charged particles with a relative charge of -1.
• Electrons have a negligible (zero) mass compared to protons and neutrons.
• Electrons are arranged in regions of space called orbitals, which define the probability of finding an electron in a certain area.
• Charge = -1, mass = 0

Question 7

Neutral atom

Answer 7

The number of electrons equals the number of protons, balancing the positive and negative charges.

Question 8

Nuclear symbols

Answer 8

A(small, top left) Z(small, bottom left) X(big left)
*A = Mass number (total number of protons and neutrons).
* Z = Atomic number (number of protons).
* X = Chemical symbol of the element (e.g. for gold).

Question 9

Ions

Answer 9

An ion is an atom or group of atoms that has gained or lost electrons, resulting in a net electrical charge.
This does not affect the number of protons or neutrons but changes the overall charge of the species.

Question 10

Anions

Answer 10

Formed when an atom gains electrons, resulting in a negative charge.

Question 11

Cation

Answer 11

Formed when an atom loses electrons, resulting in a positive charge.

Question 12

Isotope

Answer 12

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons.

Question 13

Can atoms change their number of protons and be the same atom?

Answer 13

NO
Atoms are defined by their number of protons, known as the atomic number (Z).

Question 14

Relative atomic mass

Answer 14

The relative atomic mass of an element is a weighted average of the masses of its isotopes.
Example: Relative atomic mass of chlorine.
Chlorine has two isotopes:
* Chlorine-35 (35Cl) with 75.8% abundance.
* Chlorine-37 (37Cl) with 24.2% abundance.
Calculate the relative atomic mass
((35x0.758)+(37x0.242)) = 35.48

Question 15

Physical Properties of Isotopes

Answer 15

While isotopes of the same element have nearly identical chemical properties, their physical properties can differ. These differences arise because isotopes have different masses, which can impact properties like density, melting point, and boiling point.

Question 16

Do isotopes of the same atom react differently?

Answer 16

Isotopes react chemically in the same way because they have the same number of electrons.