Atoms and orbitals

We'll start with some definitions:


 * atom : a particle that is indivisible during chemical reactions
 * element : atoms of the same atomic number

An atom = nucleus (positive charge) + electrons (negative charge)

Atomic number = number of protons in the nucleus = number of electrons (atoms are neutral - they have no overall charge)


 * electrons : have an electric charge of -1.6022 x 10-19 Coulomb and a mass of 9.11 x 10-31 kg
 * proton : nuclear particle with a positive charge equal to that of an electron (+1.6022 x 10-19 Coulomb) and a mass of 1.6726 x 10-27 kg
 * neutron : particle in the nucleus, has about the same mass as a proton but no charge


 * mass number : total number of protons and neutrons in the nucleus
 * nuclide : particular nucleus characterized by atomic number (subscript) and mass number (superscript), e.g. 12C6 is an isotope of carbon with 6 protons and 6 neutrons in the nucleus
 * isotope : atoms with the same atomic number but different mass numbers (same number of protons, same number of electrons but different number of neutrons)

quiz
{An ________ is a particle that is indivisible during chemical reactions. + atom - element - electron - proton
 * type="[]"}
 * Correct! An atom is a particle that is indivisible during chemical reactions.
 * Incorrect. An element consists of atoms of the same atomic number.
 * Incorrect. Electrons are subatomic particles with a negative charge.
 * Incorrect. Protons are nuclear particles with a positive charge.

{Atoms of the same atomic number are called ________. - atom + element - electron - proton
 * type="[]"}
 * Incorrect. An atom is the basic unit of a chemical element.
 * Correct! Atoms of the same atomic number are called an element.
 * Incorrect. Electrons are subatomic particles with a negative charge.
 * Incorrect. Protons are nuclear particles with a positive charge.

{An atom consists of a ________ with a positive charge and ________ with a negative charge. + nucleus | electrons - electrons | nucleus - proton | neutron - neutron | proton
 * type="[]"}
 * Correct! An atom consists of a nucleus with a positive charge and electrons with a negative charge.
 * Incorrect. The nucleus has a positive charge, while electrons have a negative charge.
 * Incorrect. Both protons and neutrons are found in the nucleus.
 * Incorrect. Both protons and neutrons are found in the nucleus.

{The atomic number is equal to the number of ________ in the nucleus and the number of ________. + protons | electrons - electrons | protons - neutrons | electrons - electrons | neutrons
 * type="[]"}
 * Correct! The atomic number is equal to the number of protons in the nucleus and the number of electrons.
 * Incorrect. The atomic number represents the number of protons.
 * Incorrect. Neutrons do not determine the atomic number.
 * Incorrect. The atomic number represents the number of protons.

{A ________ is a nuclear particle with a positive charge equal to that of an electron. - electron + proton - neutron - atom
 * type="[]"}
 * Incorrect. Electrons have a negative charge.
 * Correct! A proton is a nuclear particle with a positive charge equal to that of an electron.
 * Incorrect. Neutrons have no charge.
 * Incorrect. An atom is the basic unit of a chemical element.

{A ________ is a particle in the nucleus with about the same mass as a proton but no charge. - electron - proton + neutron - atom
 * type="[]"}
 * Incorrect. Electrons have a negative charge.
 * Incorrect. Protons have a positive charge.
 * Correct! A neutron is a particle in the nucleus with about the same mass as a proton but no charge.
 * Incorrect. An atom is the basic unit of a chemical element.

{The mass number is the total number of ________ and ________ in the nucleus. + protons | neutrons - electrons | protons - electrons | neutrons - protons | electrons
 * type="[]"}
 * Correct! The mass number is the total number of protons and neutrons in the nucleus.
 * Incorrect. Electrons are not counted in the mass number.
 * Incorrect. Electrons are not counted in the mass number.
 * Incorrect. Electrons are not counted in the mass number.

{A ________ is an isotope of carbon with 6 protons and 6 neutrons in the nucleus. - element - electron - proton + 12C6
 * type="[]"}
 * Incorrect. An element consists of atoms of the same atomic number.
 * Incorrect. Electrons are subatomic particles with a negative charge.
 * Incorrect. Protons are nuclear particles with a positive charge.
 * Correct! 12C6 is an isotope of carbon with 6 protons and 6 neutrons in the nucleus.

{An ________ consists of atoms with the same atomic number but different mass numbers. - element - electron + isotope - nuclide
 * type="[]"}
 * Incorrect. An element consists of atoms of the same atomic number.
 * Incorrect. Electrons are subatomic particles with a negative charge.
 * Correct! An isotope consists of atoms with the same atomic number but different mass numbers.
 * Incorrect. A nuclide is a particular nucleus characterized by atomic number and mass number.

Wikipedia

 * Atomic orbital
 * Molecular orbital
 * Electron configuration
 * Electron orbital
 * Atom