簡單原子模型：練習題

An atom of sodium can be represented as \( {}_{11}^{23}\text{Na} \).

What are the relative electrical charges of a proton and an electron?

Which row in the table correctly identifies the relative mass and relative charge of a proton?

A. Mass: 1, Charge: +1
B. Mass: 1, Charge: 0
C. Mass: Very small, Charge: +1
D. Mass: 1, Charge: –1

A metal atom reacts to form an ion with a charge of \( 2+ \). If the ion has 18 electrons and a mass number of 40, what is the identity of the element and how many neutrons does it have?

The mass number of an atom is defined as the total number of specific subatomic particles in the nucleus. Which statement correctly describes the mass number?

The 'plum pudding' model suggested that the atom was a ball of positive charge with negative electrons embedded in it. Which experimental result directly contradicted this by showing that the positive charge was concentrated in a small center?

An atom of an element is represented by the symbol \( {}_{15}^{31}\text{P} \).

Determine the number of protons and the number of neutrons located in the nucleus of this atom.

An atom of an unknown element has the electronic structure 2, 8, 7. Identify the element and state which group of the periodic table it belongs to.

Boron has two isotopes, \( ^{10}_{5}B \) and \( ^{11}_{5}B \). Compare the subatomic particles in these isotopes and explain why they react in the same way chemically.

(a) Define the term mass number of an atom. (1 point)
(b) An atom of an element is represented as \( ^{24}_{12}\text{Mg} \). Determine the number of protons, neutrons, and electrons present in this neutral atom. (3 points)

The structure of the atom is the basis for understanding chemistry. An atom of Phosphorus is represented by the symbol \( ^{31}_{15}P \).
(a) Determine the number of protons, neutrons, and electrons in a neutral atom of this isotope.
(b) State the electronic structure of this Phosphorus atom in the form \( x,y,z \).
(c) Explain why the overall electrical charge of this Phosphorus atom is zero.