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What defines an element's identity in terms of subatomic particles?
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The number of protons in the nucleus defines an element's identity.
What trend do we observe in ionization energy across a period and down a group?
Ionization energy generally increases across a period from left to right due to increasing effective nuclear charge, and decreases down a group due to increased distance of the valence electrons from the nucleus.
Explain the significance of isotopes.
Isotopes are atoms of the same element that have different numbers of neutrons, affecting their mass but not their chemical properties.
Explain the periodic trend for atomic radius.
Atomic radius increases down a group due to the addition of electron shells, and decreases across a period from left to right due to increasing nuclear charge pulling electrons closer.
What is the primary purpose of mass spectroscopy in chemistry?
Mass spectroscopy is used to determine the masses of isotopes and their relative abundances.
How does the ionic radius of cations compare to their neutral atoms?
Cations are smaller than their neutral atoms because they lose one or more electrons, reducing the electron-electron repulsion in the ion.
Differentiate between a molecule and a compound.
A molecule is a combination of two or more atoms bonded together, which can be either of the same element or different elements. A compound is a type of molecule consisting of different elements bonded together.
What is the significance of Hund's Rule in electron configuration?
Hund's Rule states that electrons will fill degenerate orbitals singly before pairing up in order to minimize electron-electron repulsions and stabilize the atom.
What is the Aufbau principle in electron configuration?
The Aufbau principle states that electrons occupy the lowest energy orbitals first before filling higher energy levels.
How do homogeneous mixtures differ from heterogeneous mixtures?
Homogeneous mixtures have a uniform composition throughout, while heterogeneous mixtures have a non-uniform composition.
What makes electronegativity important, and how does it trend on the periodic table?
Electronegativity measures an atom's ability to attract electrons in a chemical bond. It increases up a group and across a period from left to right, excluding noble gases.
Describe the process to determine the empirical formula of a compound.
To determine the empirical formula, find the percent composition of each element, convert these percentages to moles, and then divide by the smallest number of moles to obtain the lowest whole number ratio of atoms.
What information does the atomic number of an element provide?
The atomic number indicates the number of protons in the nucleus of an atom of the element.
Define molar mass and its significance in chemistry.
Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It allows conversion between the mass of a substance and its amount in moles.
Define electron affinity and its general trend on the periodic table.
Electron affinity is the energy change that occurs when an electron is added to a neutral atom. It generally increases up a group and across a period from left to right, excluding noble gases.
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