Comprehensive Atomic Structure and Chemistry: Atoms, Molecules, Ions, and Elements

What are atoms?

Atoms are the smallest particles of an element that have the same properties as the element itself.

What is a molecule?

A molecule is a group of atoms connected together, formed when atoms share electrons.

What is the size of an atom?

Atoms are about 2 × 10⁻¹⁰ meters in radius and are mostly empty space.

What is located at the core of an atom?

The nucleus, which contains protons and neutrons.

What experiment did Rutherford conduct to discover the internal structure of atoms?

Rutherford's gold foil experiment.

What did Rutherford's gold foil experiment demonstrate?

Most alpha particles went straight through the foil and some bounced back, indicating that atoms are mostly empty space.

What causes the chemical properties of atoms?

The locations of the electrons in atoms.

What is an ion?

An ion is an atom that has gained or lost electrons, resulting in a non-zero overall charge.

What is the electrical charge of normal atoms?

Normal atoms are electrically neutral, with each proton matched by an electron.

Brownian Motion

Brown observed that microscopic particles (like pollen) suspended in liquid move in a random, jittery dance. In 1905, Albert Einstein theorized this was caused by invisible water molecules constantly colliding with the particles

What happens when hydrogen gas combines with oxygen gas?

Two liters of hydrogen gas will combine with two liters of oxygen gas to make water, with no leftovers.

What happens to opposite charges?

Opposite charges attract.

What happens to like charges?

Like charges repel.

How do protons and electrons interact?

Protons and electrons attract each other.

What is the role of neutrons in an atom?

Neutrons act like glue, allowing protons to stay together.

What is the charge of an atom's nucleus?

The nucleus is positively charged.

How do the number of electrons compare to protons in a neutral atom?

In a neutral atom, there are as many electrons as protons.

What is required for an object to be electrically charged?

An object must have an unequal number of electrons and protons.

Can electrons be created or destroyed?

Electrons cannot be created or destroyed; they are transferred from one atom to another.

What does Coulomb's Law state?

The force between charged particles varies directly as the product of the charges and inversely as the square of the distance between them.

What is the SI unit of charge?

The SI unit of charge is the coulomb, abbreviated C.

What does a coulomb represent in terms of electrical current?

A coulomb represents the amount of charge that passes through a common 100-W light bulb in about one second.

What is the relationship between force and charge according to Coulomb's Law?

Force and charge are directly proportional.

What is the relationship between force and distance according to Coulomb's Law?

Force and distance are inversely proportional.

What does a negative electric force indicate?

A negative electric force indicates attraction.

What does a positive electric force indicate?

A positive electric force indicates repulsion.

What three subatomic particles can atoms contain?

Protons, neutrons, and electrons.

What is the mass of an atom primarily located?

In its nucleus.

How can we identify different types of atoms?

By the number of protons they have.

What is the significance of the periodic table?

It lists the different types of atoms.

What type of atom is diamond composed of?

Carbon.

How many atoms are there approximately in a gram of water?

About 10^23 atoms.

What is Brownian motion evidence of?

The existence of atoms.

What are elements?

Substances that consist of only one type of atom.

How many elements are known?

Around 115 elements.

What five elements primarily compose living things?

Oxygen (O), carbon (C), hydrogen (H), nitrogen (N), and calcium (Ca).

What is the lightest element?

Hydrogen.

What is a compound?

A substance made of atoms of different elements combined in a fixed proportion.

What distinguishes compounds from mixtures?

Compounds have fixed proportions of their constituent atoms, while mixtures do not.

What are nucleons?

The principal building blocks of the nucleus, consisting of protons and neutrons.

What is an isotope?

Atoms of the same element having different numbers of neutrons.

What defines an atom's atomic number?

The number of protons in the nucleus.

What are the two types of electric charge?

Positive and negative.

What is the charge of protons and electrons?

Protons are positive, and electrons are negative.

What happens when the number of electrons differs from the number of protons in an atom?

The atom has a net charge and is called an ion.

How does the arrangement of electrons affect an atom?

It dictates the atom's chemical properties.