NGS Ch 09 - Section 1: Atomic Structure

What are the basic building blocks of matter?

• Molecules

• Compounds

• Elements

• Mixtures

Answer explanation

The basic building blocks of matter are elements. Elements are pure substances that cannot be broken down into simpler substances and are the fundamental components that combine to form molecules and compounds.

Tags

NGSS.MS-PS1-1

What is the smallest piece of matter that still has the element’s properties?

• Molecule

• Atom

• Electron

• Compound

Answer explanation

The smallest piece of matter that retains the properties of an element is an atom. Atoms consist of protons, neutrons, and electrons, and they define the chemical identity of an element, unlike molecules or compounds which are made of multiple atoms.

Which particle in an atom carries a positive electric charge?

• Quark

• Proton

• Neutron

• Electron

Answer explanation

The proton is the positively charged particle in an atom, found in the nucleus. In contrast, neutrons have no charge, and electrons carry a negative charge. Quarks are constituents of protons and neutrons.

What is the chemical symbol for iron?

• Ir

• In

• Fe

• I

Answer explanation

The chemical symbol for iron is 'Fe', derived from its Latin name 'ferrum'. The other options, 'Ir' for iridium, 'In' for indium, and 'I' for iodine, are incorrect.

Who is often called the father of modern chemistry?

• Antoine Lavoisier

• Robert Boyle

• Dmitri Mendeleev

• John Dalton

Answer explanation

Antoine Lavoisier is often called the father of modern chemistry due to his role in establishing the law of conservation of mass and his work in chemical nomenclature, which laid the foundation for modern chemical science.

Which model of the atom did Niels Bohr introduce?

• Electron Cloud Model

• Solar System Model

• Billiard Ball Model

• Plum Pudding Model

Answer explanation

Niels Bohr introduced the Solar System Model of the atom, where electrons orbit the nucleus in defined paths, similar to planets around the sun. This model was a significant advancement in atomic theory.

Who discovered the electron?

• J.J. Thomson

• Marie Curie

• Ernest Rutherford

• Robert Millikan

Answer explanation

J.J. Thomson discovered the electron in 1897 through his experiments with cathode rays, demonstrating that they were composed of negatively charged particles, which he named electrons.

What did Aristotle believe the world was made of?

• Atoms

• Four elements

• Compounds

• Molecules

Answer explanation

Aristotle believed the world was made of four elements: earth, water, air, and fire. This theory was foundational in ancient philosophy, contrasting with later atomic theories.

What is the maximum number of electrons the last energy level can hold, except in helium and hydrogen?

• 2

• 4

• 8

• 6

Answer explanation

The maximum number of electrons in the last energy level, except for helium and hydrogen, is 8. This is based on the octet rule, which states that atoms are most stable with 8 electrons in their outer shell.

Who created today’s Periodic table based on atomic numbers?

• Henry Moseley

• John Dalton

• Robert Boyle

• Dmitri Mendeleev

Answer explanation

Henry Moseley redefined the periodic table by arranging elements according to their atomic numbers rather than atomic mass, which led to the modern structure we use today.