Atomic Structure

The identity of an element is defined by the number of ______________.

To calculate the number of neutrons in an atom, you subtract the number of protons from the _________________.

The weighted average of the mass of the atoms in a naturally occurring sample of an element is called the ____________________

The subatomic particle with no charge is the ________________.

Atoms with the same number of protons but different numbers of neutrons are called __________________.

Which of these statements is included in Dalton's theory?

• Chemical reactions occur when atoms are separated, joined, or rearranged.

• Some but not all elements are composed of atoms.

• Atoms of the same element can have different numbers of protons.

• Atoms are divisible.

Which of the following statements is incorrect?

• Electrons are negatively charged.

• Protons are positively charged.

• Neutrons have no charge.

• Atoms are positively charged.

Which of the following statements is not consistent with the results obtained in Rutherford's gold foil experiment?

• The nucleus of the atoms is positively charged.

• The nucleus of an atom contains almost all the mass of the atom.

• Atoms are composed mainly of empty space.

• Electrons are contained in the nucleus of an atom.

What is the atomic number and the mass number of an atom with 11 protons and 12 neutrons?

• atomic number = 11 and mass number = 12

• atomic number = 12 and mass number = 11

• atomic number = 11 and mass number = 23

• atomic number = 23 and mass number = 11

An atom of hydrogen-2 contains

• 2 protons, 2 electrons, and 2 neutrons

• 2 protons, 2 electrons, and 4 neutrons

• 1 proton, 1 electron, and 1 neutron

• 1 proton, 1 electron, and 0 neutrons