The Amazing Atom and Modern Atomic Theory

These flashcards cover the key concepts and principles from the lecture notes on atomic theory and the structure of atoms.

What is the basic form of any element?

An atom.

What are the three subatomic particles in an atom?

Protons, neutrons, and electrons.

Where are protons located in the atom?

In the nucleus.

What charge do neutrons have?

Neutral charge.

What happens to an atom when it has more protons than electrons?

It becomes a positively charged ion.

Who first introduced the idea of atoms as indestructible particles?

Democritus.

What are the four elements according to ancient Greek philosophy?

Fire, Earth, Water, Air.

What did Dalton propose in 1808 regarding matter?

Matter is composed of tiny, indivisible particles called atoms.

What does the Law of Conservation of Mass state?

In any physical or chemical change, matter is neither created nor destroyed.

What is the Law of Definite Proportions?

Compounds are always composed of the same elements in the same proportion by mass.

What is the Law of Multiple Proportions?

When two elements form more than one compound, the masses of one element that combine with a fixed mass of the other are in a ratio of small whole numbers.

Who discovered the electron and what was significant about it?

J.J. Thomson discovered the electron, showing that atoms are made up of smaller charged particles.

What did Rutherford discover in his Gold Foil Experiment?

Most of the atom's mass is concentrated in a small, dense, positively charged nucleus.

What defines an element?

The number of protons in its nucleus.

What are isotopes?

Atoms of the same element that have different numbers of neutrons.

What is the function of valence electrons in ion formation?

They determine the charge of the ion based on gain or loss.

How is atomic mass calculated?

As the weighted average of the isotopes of an element based on their abundance.

What do metals typically do in chemical reactions?

Lose electrons.

What is the charge of cations and anions?

Cations are positively charged, and anions are negatively charged.

What is unique about the charge of an atom's protons and electrons when combined?

They cancel each other out, resulting in a neutral charge.

True or false? Matter is composed of atoms (tiny little spheres) that are solid and bounce.

True

True or false? Atoms are fundamental, indestructible, and indivisible particles (like Democritus said).

Fundamental - True, Indestructible - True, Indivisible - False (Subatomic particles are smaller, atoms can’t disappear!)

True or false? All atoms of a given element were exactly alike.

False, as isotopes exist with varying numbers of neutrons and therefore different masses.

True or false? Atoms of one element cannot change into another element, but they can combine in simple whole ratios to make up all the different compounds we find in nature.

False; nuclear changes can happen where an atom of one element can change into another element, but it is still True that atoms can combine in simple whole ratios to form compounds.

True or false? In a chemical reaction, atoms are separated, combined or rearranged.

True - not creating nor destroying matter.

What are corpuscles?

Small things/particles

What was Rutherford’s Goal?

He wanted to prove Thompson’s plum putting model was true.

Who discovered the neutron and how?

James Chadwick discovered the neutron through his experiment where he bombarded beryllium with alpha particles, observing a highly penetrating, uncharged radiation that could eject protons from paraffin.