Chemistry Chapter 4 Exam Knowt

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What is the charge and mass of an electron?

An electron has a negative charge and a negligible mass.

What does the Rutherford Model describe?

The Rutherford Model describes the nuclear structure of the atom but does not detail electron arrangement.

Who proposed the quantum model for the hydrogen atom?

Niels Bohr proposed the quantum model for the hydrogen atom.

What is Planck's Constant?

Planck's Constant (h) is valued at $6.626 \times 10^{-34} \text{ J} \cdot \text{s}$.

What does the photoelectric effect demonstrate?

The photoelectric effect demonstrates that electrons are emitted from a metal's surface when light at or above a certain frequency shines on it.

What is the significance of the quantum number ($n$)?

The quantum number ($n$) indicates the allowed energy levels of an electron in an atom.

What did Bohr's model explain?

Bohr's model explained the spectral lines of hydrogen but failed to explain those of other elements.

What did Louis de Broglie hypothesize about electrons?

He hypothesized that particles, including electrons, exhibit wavelike behaviors.

What is the Heisenberg Uncertainty Principle?

It states that it is impossible to know both the velocity and position of a particle simultaneously.

What is the Quantum Mechanical Model?

A model that describes electrons as existing in electron clouds rather than in predetermined orbits.

What does the Schrödinger Wave Equation describe?

It treats electrons as waves and applies to elements beyond hydrogen.

What are Quantum Numbers?

Numbers that describe atomic orbitals and the electrons they contain, including distance from the nucleus, shape, orientation, and spin.

What does the Principal Quantum Number ($n$) indicate?

It indicates the main energy level occupied by electrons, with higher $n$ values corresponding to larger orbitals and higher energy.

What is the range of values for the Angular Momentum Quantum Number ?

It can range from 0 to ($n$-1) and indicates the shape of the orbital.

What does the Magnetic Quantum Number indicate?

It indicates the orientation of an orbital about the three axes in space.

How many electrons can each orbital hold?

Each orbital can hold a maximum of 2 electrons.

What is the Spin Quantum Number ?

It indicates the direction of the electron spin, with values of +1/2 (clockwise) or -1/2 (counterclockwise).

What is the formula to determine the maximum number of electrons in a shell?

The formula is $2n^2$, where $n$ is the principal quantum number.

What is the Aufbau Principle?

It states that each electron occupies the lowest energy orbital available.

What does the Pauli Exclusion Principle state?

No two electrons in the same atom can have the same set of quantum numbers; electrons in the same orbital must have opposite spins.

What is Hund's Rule?

Single electrons with the same spin must occupy each equal-energy orbital before pairing up with opposite spins.

What are Valence Electrons?

Electrons located in the outermost energy level of an atom.

What is an Octet?

A stable configuration of 8 electrons in the outer shell.

What is Noble Gas Configuration?

A configuration where the outermost energy level is occupied by 8 electrons, achieving stability.

What do the A numbers on the periodic table indicate?

They indicate the number of valence electrons for elements in those groups.

What are Electron-Dot Structures?

Diagrams that represent an element's chemical symbol and its valence electrons as dots.