Atomic Theory and Structure Flashcards

Flashcards derived from the provided notes covering historical atomic models, subatomic particles, Dalton's postulates, isotopes, and average atomic mass.

What is the definition of atomic structure provided in the notes?

The idea that matter is made up of atoms, which are the smallest pieces of matter.

What did Democritus suggest about matter and atoms between 460 - 370 B. C. (400 BC)?

He suggested that all matter is made of indivisible particles called atoms.

What are Dalton's five postulates regarding atoms and matter?

1. All matter is made up of tiny, indivisible particles called atoms. 2. All atoms of a specific element are identical in mass, size, and other properties. 3. Atoms of different element exhibit different properties and vary in mass and size. 4. Atoms of different elements can combine with each other in fixed whole number ratios to form compounds. 5. Atoms can be rearranged, combined, or separated in chemical reactions but not created or destroyed.

What model did John Dalton propose in 1810?

A solid sphere model based on the concept that all mass is equal.

What does the law of conservation of mass state?

Mass is never created or destroyed in any process.

What experiment did JJ Thomson conduct in 1897, and what were his key findings and model?

He used a Cathode Ray Tube, discovered the electron, and proposed the Plum Pudding Model.

What experiment did Ernest Rutherford conduct, and what did he discover about the atom?

He conducted the Gold foil experiment, discovered the positively charged nucleus, established that masses are in the nucleus and proton, and determined that atoms are mostly empty space (Nuclear Model / Planetary Model).

What model did Niels Bohr propose in 1913?

The Bohr Model, which states that electrons differ in energy levels.

What concept did Shrodinger and Heisenberg introduce in 1920 regarding electrons?

They stated that you cannot know both the position and energy level of an electron.

How is Heisenberg's Uncertainty Principle explicitly defined in the notes?

It is impossible to know an electron's exact position and exact momentum.

What are the location, charge, and relative size of a proton?

Location: Nucleus; Charge: $+1$; Relative size: Large / Amu.

What are the location, charge, and relative size of a neutron?

Location: Nucleus; Charge: $0$; Relative size: Large / Amu.

What are the location, charge, and relative size of an electron?

Location: e cloud; Charge: $-1$; Relative size: tiny Amu.

What does Amu stand for?

Atomic mass unit.

What is the atomic number and why is it important?

It is the number of protons, which determines the identification of the element.

What is the equation for the mass number of an atom?

$$\text{Mass number} = \text{protons} + \text{neutrons}$$

What is an isotope?

Atoms of the same element that have different masses.

According to the notes, what is the average atomic mass of Carbon and what three isotopes of Carbon are listed?

The average atomic mass of Carbon is $12.011$, and its listed isotopes are C-12, C-13, and C-14.

What is the definition of Average Atomic Mass?

The weighted average of the atomic masses of the naturally occurring isotopes of an element.

What formula is provided for calculating a weighted average atomic mass?

$$\frac{(\text{Mass} \times \%) + (\text{Mass} \times \%) + (\text{Mass} \times \%)\dots}{100}$$