Exploring Atoms and Molecules

What is the main idea of atomic theory?

• Matter can exist without atoms.

• Atoms are only found in gases.

• All atoms are identical in size and mass.

• The main idea of atomic theory is that all matter is made up of atoms.

Who proposed the first atomic theory?

• Albert Einstein

• John Dalton

• Niels Bohr

• Erwin Schrödinger

What are the three main subatomic particles?

• Quarks, Gluons, Neutrons

• Protons, Neutrons, Electrons

• Electrons, Positrons, Neutrons

• Protons, Neutrons, Photons

What is the charge of a proton?

• +1 elementary charge

• +2 elementary charge

• 0 elementary charge

• -1 elementary charge

What is the charge of an electron?

• 0 coulombs

• -1.602 x 10^-19 coulombs

• 1.602 x 10^-19 coulombs

• -1.602 x 10^19 coulombs

What is the mass of a neutron compared to a proton?

• The mass of a neutron is slightly greater than that of a proton.

• The mass of a neutron is twice that of a proton.

• The mass of a neutron is significantly less than that of a proton.

• The mass of a neutron is equal to that of a proton.

Define the term 'atomic number'.

• The atomic number is the number of protons in the nucleus of an atom.

• The atomic number is the total number of electrons in an atom.

• The atomic number is the number of neutrons in the nucleus of an atom.

• The atomic number is the mass of an atom measured in atomic mass units.

What does the mass number of an atom represent?

• The mass number indicates the atomic weight of an element.

• The mass number represents the total number of protons only.

• The mass number is the number of electrons in an atom.

• The mass number represents the total number of protons and neutrons in an atom.

How do you calculate the number of neutrons in an atom?

• Number of neutrons = Atomic number - Atomic weight

• Number of neutrons = Atomic mass number - Atomic number

• Number of neutrons = Atomic mass number - Mass number

• Number of neutrons = Atomic number + Atomic mass number

What is the mole concept in chemistry?

• The mole concept defines a mole as 1,000 particles per unit.

• The mole concept relates the amount of substance to mass and number of particles, defined as 6.022 x 10^23 entities per mole.

• The mole concept is only applicable to gases and not solids or liquids.

• The mole concept measures temperature in chemical reactions.