Flashcard: Fundamentals of Atomic Structure and Periodic Trends — 14 carte

Atomic theory — founder?

Democritus proposed atoms as indivisible particles.

Dalton’s atomic theory — claim?

Atoms of the same element are identical; different elements have different atoms.

Thomson’s model — feature?

Atom contains electrons within a positive sphere.

Rutherford’s model — discovery?

Nucleus is dense and positively charged.

Bohr’s model — electrons?

Electrons occupy fixed energy levels.

Cathode ray tube — deflects?

Electrons toward positive, protons toward negative plates.

Atomic number (Z) — definition?

Number of protons in an atom.

Mass number (A) — formula?

Protons plus neutrons (A = Z + neutrons).

Isotopes — difference?

Same Z, different neutrons.

Principal quantum number — symbol?

n; labels electron shells.

Hund’s Rule — principle?

Electrons occupy separate orbitals before pairing.

Ionization energy — trend?

Increases across a period, decreases down a group.

s-block elements — last orbital?

s orbital, group 1 and 2.

Cr and Cu — electron config?

Prefer half-filled (Cr) and fully filled (Cu) d-subshells.