Atomic Structure and Electron Configuration

These flashcards cover key concepts from the lecture on atomic structure and electron configuration.

What did the cathode rays experiment conclude about the particles in cathode rays?

They are made up of very small, negatively charged particles known as electrons.

What does the gold foil experiment suggest about the structure of an atom?

It suggests that there is a tiny and dense region called the nucleus at the center of the atom where most of the mass is concentrated.

What is an atomic number?

The atomic number is the number of protons present in the atom.

How do you calculate the mass number of an atom?

The mass number is calculated as the number of protons plus the number of neutrons.

What are isotopes?

Isotopes are different atoms of the same element that have the same atomic number but different mass numbers due to varying numbers of neutrons.

How is atomic mass defined?

The atomic mass of an element is the average atomic masses of its isotopes.

What does the electron's dual nature refer to?

It means that the electron can behave as both a particle and a wave.

What states can an electron occupy in an atom?

An electron can occupy the ground state or excited states.

What happens when an electron moves from an excited state to the ground state?

It emits energy, which is the basis for atomic spectra.

What is the Aufbau principle?

The Aufbau principle states that electrons occupy the lowest energy orbitals available.

What is Hund's Rule?

Hund's Rule states that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals.

What is the noble gas notation in electron configuration?

It is a method of simplifying electron distribution by representing all lower filled orbitals up to the closest noble gas in brackets.

What shapes do s and p orbitals have?

S orbitals have a spherical shape, and p orbitals have a dumbbell shape aligned along the x, y, and z axes.