Honors Chem Chapter 5

What were some limitations of Rutherford's atomic model?

-It explained only a few simple properties of atoms -It could not explain the chemical properties of elements (example: couldn't explain why iron scroll changes colors when heated)

How are a ladder and Bohr's model similar?

A person on a ladder cannot stand between rungs. Similarly, the electrons in an atom cannot exist between energy levels. The energy levels in atoms are unequally spaced. The higher energy levels are closer together. The higher the energy level occupied by an electron, the less energy it takes to move from that energy level to the next higher energy level. In general, the higher an electron is on the energy ladder, the farther it is from the nucleus.

What did Bohr propose in his model of the atom?

Bohr proposed that an electron is found only in specific circular paths, or orbits, around the nucleus

Compare and Contrast the Quantum Mechanical Model to the Bohr Model

Compare: Like the Bohr Model, the quantum mechanical model of the atom restricts the energy of electrons to certain values Contrast: Unlike the Bohr model, however, the quantum mechanical model does not specify an exact path the electron takes around the nucleus

Key Concept about Energy Sublevels

Each energy sublevel corresponds to one or more orbitals of different shapes. The orbitals describe where an electron is likely to be found

The Bohr Model

Each possible electron orbit in Bohr's model has a fixed energy which are called energy levels

What did Bohr change about Rutherford's model?

He added that energy of an atom changes when the atom absorbs or emits light. The Bohr model explains how the energy levels of electrons in an atom change when the atoms emits light

How did Austrian physicist Erwin Schrodinger create the Quantum Mechanical Model?

He used new theoretical calculations and experimental results to devise and solve a mathematical equation describing the behavior of the electron in a hydrogen atom. The modern explanations of electron behavior come from the mathematical solutions to the Schrodinger equation.

What role does probability play in finding an electron?

Probability describes how likely it i sot find an electron in a particular location around the nucleus of an atom

Which letters denote atomic orbitals? How many orbitals of each are there?

S, P, D, F. The s orbitals are spherical, and the p orbitals are dumbbell shaped. There is one s orbital, 3 p orbitals, 5 d orbitals, and 7 f orbitals. Each orbital can hold a maximum of two electrons. In the first energy level (n=1), there is only one sublevel, called 1s. The second energy level (n=2) has two sublevels, 2s and 2p. The third has 3 sublevels, 3s, 3p and 3d. The fourth has 4 sublevels, 4s, 4p, 4d, and 4f. The principal quantum number (n=) always equals the maximum amount of sublevels within that energy level.

What do solutions to the Schrodinger equation give?

Solutions to the Schrodinger equation give the energies, or energy levels an electron can have. For each energy level, the Schrodinger equation also leads to a mathematical expression, called an atomic orbital.

What is a quantum of energy?

The amount of energy required to move an electron from one energy level to another energy level

How are energy levels in quantum mechanical model are labeled? For each principal energy level greater than 1 there there how many orbitals? What do orbitals describe?

The energy levels of electrons in the quantum mechanical model are labeled by principal quantum numbers (n). These numbers are assigned the values n=1, 2, 3, 4 and so forth. For each principal energy level greater than one, there are several orbitals with different shapes and at different energy levels. These energy levels within a principal energy level constitute energy sublevels.

What does a "fuzzy could like region" represent in the quantum mechanical model?

The probability of finding an electron in a certain volume of space. The cloud is more dense where the probability of finding an electron is high.

The Quantum Mechanical Model

The quantum mechanical model determines the allowed energies an electron can have and how likely it is to find the electron in various locations around the nucleus. (Austrian physicist Erwin Schrödinger. It is the modern description of the electrons in atoms.)

What is an atomic orbital?

a region of space in which there is a high probability of finding an electron.

What is an easy way to calculate the total number of electrons in an energy level?

the formula 2n squared, where n is the energy level. In the first energy level, n=1, so 2(1) squared=2. In the fifth energy level, n=5 so 2(5) squared=50.