QCM : Fundamentals of Atomic Structure — 9 questions

Explication

Metals are preferred in electrical wiring because they are good conductors of electricity, which allows efficient transmission of electrical current. Non-metals are poor conductors and are not suitable for conducting electricity in wiring.

Explication

Protons carry a positive electric charge, which is a fundamental property of subatomic particles and is explicitly stated in the content. Neutrons are neutral, and electrons carry a negative charge. The charge of a proton does not vary depending on the atom, making positive (+) the correct answer.

Explication

Dmitri Mendeleev is credited with proposing the concept of group properties in the periodic table, as he organized elements into groups with similar properties based on their valence electrons, which is a fundamental aspect of the periodic system.

Explication

A proton is a positively charged particle located in the nucleus of an atom, which determines the atomic number and element identity.

Explication

The Bohr model, which introduced the idea of electrons orbiting the nucleus in specific shells, was established in 1913 by Niels Bohr. This model was a significant development in atomic theory, providing a clear explanation of the arrangement of electrons in atoms.

Explication

Particle charges, specifically the positive charge of protons and the negative charge of electrons, play a crucial role in maintaining the atom's electrical neutrality and facilitating chemical bonding. The charges allow atoms to attract or repel each other, leading to the formation of molecules and compounds.

Explication

Groups are vertical columns in the periodic table where elements share similar outer electron configurations, influencing their chemical properties. Periods are horizontal rows where elements have the same number of electron shells, affecting their atomic size and energy levels. This structural difference is fundamental to the organization of the periodic table.

Explication

The primary cause of the change in period properties across a period is the increase in the number of electron shells, which affects atomic size and other properties. As you move across a period, the number of shells remains the same, but the number of electrons in the outer shell increases, influencing chemical properties. The increase in protons affects atomic number but is not the direct cause of period property changes; the addition of electrons to the outer shell is a consequence, not the cause. The change from metals to non-metals occurs across groups, not within a period.

Explication

The nuclear mass is primarily determined by the total number of protons and neutrons in the nucleus, which is called the mass number. Electrons contribute negligibly to the nuclear mass, and the atomic number only counts protons, not neutrons.