Chemistry: Periodic Table and Atomic Structure

A chart that organizes elements by their atomic number, electron configuration, and recurring chemical properties.

The small number above an element's symbol, indicating the number of protons in the atom's nucleus.

A column on the periodic table that groups elements with similar chemical properties.

A row on the periodic table that indicates the highest energy level of an element's electrons.

Elements that generally lack metallic properties, such as luster, malleability, and ductility.

Thomson's experiment suggested the existence of negatively charged particles called electrons using cathode ray tubes.

Rutherford's experiment provided the first evidence of a dense, positively charged center in the atom, later identified as the nucleus.

Chadwick discovered the neutron, a neutral particle found in the nucleus, with a mass slightly greater than a proton.

Millikan determined the charge of an electron using the oil drop experiment, a groundbreaking discovery that helped understand atomic structure.

Atomic models describe the structure of atoms, with various models evolving to explain observations and address inconsistencies.

The number of protons in an atom's nucleus, which determines the element's identity.

Different versions of an element with the same number of protons but different numbers of neutrons.

The sum of protons and neutrons in an atom's nucleus.

A symbolic representation of a compound using chemical symbols and subscripts to indicate the number of atoms of each element.

A chemical compound formed by the ionic bond between potassium (K) and oxygen (O) atoms.

The Bohr model describes electrons as orbiting the nucleus in fixed energy levels or 'stationary orbits,' meaning they don't emit energy while in these orbits.

Lewis structures use dots to represent valence electrons, showing how atoms share or transfer electrons to form bonds. These structures help visualize the arrangement of atoms and electrons in molecules.

Ionic bonds are formed when one atom gives an electron to another atom, resulting in positively and negatively charged ions that attract each other. Examples include NaCl and MgS.

Covalent bonds are formed when atoms share electrons to achieve a stable octet configuration. Covalent bonds occur between nonmetals, like in water ($H_2O$) or methane ($CH_4$).

Metallic bonds occur in metals where electrons are delocalized and move freely, forming a 'sea of electrons.' This free movement explains the excellent conductivity of metals.

Attractions that occur between molecules. They are weaker than the forces that hold atoms together within a molecule (intramolecular forces) but are strong enough to influence the physical properties of matter.

Forces that arise from temporary, instantaneous dipoles, which are caused by the random movement of electrons in molecules. These forces are present in all molecules and atoms.

Attractions between polar molecules, molecules with permanent dipoles due to uneven electron distribution. These molecules have regions with partial positive and negative charges.

The melting point is the temperature at which a substance transitions from a solid to a liquid. The boiling point is the temperature at which a substance transitions from a liquid to a gas.

The state of matter (solid, liquid or gas) of substances can be predicted at standard conditions by observing their melting and boiling points. Higher melting and boiling points suggests stronger intermolecular forces.

A diagram showing the arrangement of atoms and electrons in a molecule, illustrating bonding and lone pairs.

A type of chemical bond formed by the sharing of electrons between atoms.

A bond formed when one atom loses an electron and another gains it, creating oppositely charged ions that attract each other.

A type of chemical bonding found in metals, where electrons are freely shared among a lattice of positively charged ions.

A regular, repeating arrangement of positive and negative ions in a crystal structure, held together by electrostatic forces.

A chemical family in the periodic table known for their tendency to form ionic bonds by readily losing one electron.

A chemical family in the periodic table known for their tendency to form ionic bonds by readily losing two electrons.

A chemical family in the periodic table known for their tendency to gain electrons to form negative ions.