Skip to main content
Back

Atoms and Chemical Bonding in General Biology

Control buttons has been changed to "navigation" mode.
1/21
  • What is matter?

    Matter is anything that takes up space and has mass, including organisms, rocks, and oceans.

  • What is an atom?

    An atom is the smallest unit of an element and the smallest unit of matter.

  • What are the three main subatomic particles of an atom?

    Protons (positively charged), neutrons (neutral), and electrons (negatively charged).

  • Where are protons, neutrons, and electrons located in an atom?

    Protons and neutrons are in the nucleus; electrons orbit in electron shells around the nucleus.

  • What is the atomic number of an element?

    The atomic number is the number of protons in the nucleus of an atom and defines the element.

  • What is the mass number of an atom?

    The mass number is the total number of protons and neutrons in the nucleus.

  • What is the difference between atomic mass and mass number?

    Atomic mass is the average mass of all isotopes of an element; mass number is the total protons plus neutrons in one atom.

  • What are electron shells or orbitals?

    Electron shells are 3D regions around the nucleus where electrons are found, arranged in energy levels or shells.

  • How many electrons can the first and second electron shells hold?

    The first shell holds up to 2 electrons; the second shell holds up to 8 electrons.

  • What are valence electrons?

    Valence electrons are the electrons in the outermost energy shell of an atom, important for chemical bonding.

  • What is the octet rule?

    The octet rule states atoms are most stable when their valence shell is full, usually with 8 electrons.

  • What are isotopes?

    Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.

  • What is a chemical bond?

    A chemical bond is an attractive force between atoms that holds them together to form molecules or compounds.

  • What is the difference between intramolecular and intermolecular bonds?

    Intramolecular bonds occur within a molecule; intermolecular bonds occur between different molecules.

  • What are covalent bonds?

    Covalent bonds form when two atoms share one or more pairs of electrons.

  • What is the difference between polar and nonpolar covalent bonds?

    Nonpolar covalent bonds share electrons equally; polar covalent bonds share electrons unequally due to different electronegativities.

  • What is electronegativity?

    Electronegativity measures an atom's attraction for electrons, ranging from 0 to 4.

  • What are noncovalent bonds?

    Noncovalent bonds are interactions between atoms without sharing electrons, including ionic, hydrogen, and Van der Waals bonds.

  • What are ions, anions, and cations?

    Ions are charged atoms or molecules; anions are negatively charged (gain electrons); cations are positively charged (lose electrons).

  • What is an ionic bond?

    An ionic bond is an electrical attraction between oppositely charged ions (cations and anions).

  • What is a hydrogen bond?

    A hydrogen bond is a weak interaction between a hydrogen atom bonded to a highly electronegative atom (F, O, or N) and another electronegative atom.