Atoms and Periodic Table Chemistry Test

Atomic Number and Elements

• Zirconium has an atomic number of 40.
• Rubidium (Rb) is classified as an alkali metal.

Electron Configuration and Atomic Structure

• When outermost electrons are removed from a calcium atom, it becomes a cation with a smaller radius.
• The angular momentum quantum number indicates the shape of an orbital.
• Electrons fill orbitals in order of increasing energy from left to right in the periodic table.
• The valence electrons of aluminum (Al) are 3, available for bonding.

Isotopes and Neutrons

• Hydrogen has three isotopes: 1H, 2H, and 3H, differentiated by the number of neutrons (0-2).

Historical Models of the Atom

• Democritus was the first to propose the existence of atoms.
• Ernest Rutherford's gold foil experiment revealed that most positive particles passed through gold foil, while some bounced back, indicating a small dense nucleus.
• Niels Bohr described electrons as orbiting the nucleus in discrete paths, forming the planetary model.

Ionization Energy Trends

• Ionization energy generally increases across a period, but shows a decrease between groups 2 and 13 due to the full s orbital shielding the electron in the p orbital.
• Ionization energy decreases from top to bottom in a group because electrons are farther from the nucleus.

Quantum Numbers and Electron Configuration

• For n = 2, the possible l values are 0 and 1; valid m values for a subshell of n = 2 are -1, 0, and 1.
• For selenium (Se), valence electrons reside in the s and p orbitals.
• Noble gas notation for elements with valence electrons in the 5s subshell includes krypton (Kr).

Reactivity and Atomic Radius

• Sodium is recognized as the most reactive element.
• Antimony (Sb) has the largest atomic radius among the elements.

Modern Atomic Theory vs. Dalton's Theory

• Modern atomic theory supports the idea that electrons exist in probable locations around the nucleus, contrary to Dalton's theory which lacked this understanding.
• J.J. Thomson's experiment disproved Dalton’s notion that atoms contain solely protons.

Subatomic Particles

• A labeled particle marked with X can either be identified as a nucleus or a proton.
• Positive charge in an atom occupies a very small volume, as demonstrated in Rutherford's experiment.

Test your knowledge on atomic structure and the periodic table with this quiz. It covers topics like atomic numbers, alkali metals, and electron configurations. Perfect for chemistry students looking to reinforce their understanding.