Chemistry Chapter 2: Atomic Structure, Ions, and Molecules

What does the Law of Conservation of Matter state?

Mass (or matter) cannot be created or destroyed. It can only be changed from one form into another.

Explain the Law of Definite Proportions.

A given compound always contains exactly the same proportion of elements by mass

What is the Law of Multiple Proportions?

Different compounds made from the same elements combine in whole-number ratios.

What major contributions did J.J. Thomson make to atomic theory?

Discovered the electron and proposed the plum pudding model of the atom.

What was Robert Millikan's contribution to atomic theory?

Measured the charge and mass of the electron

What did Ernest Rutherford discover?

protons and the nucleus

What was James Chadwick's contribution to atomic theory?

Discovered the neutron.

What contributions did Marie Curie make to atomic theory?

research on radioactivity

What was Dmitri Mendeleev known for?

Created the periodic table of elements based on atomic mass and properties.

What are the main points of Dalton's Atomic Theory?

1. All matter is composed of atoms. 2. Atoms of a given element are identical. 3. Atoms cannot be created or destroyed. 4. Compounds are formed by combining atoms in fixed ratios.

Define atoms, ions, elements, molecules, and compounds.

Atoms are the smallest units of matter; ions are charged atoms; elements are pure substances made of one type of atom; molecules are two or more atoms bonded together; compounds are substances formed from two or more different elements.

Describe the atomic structure including subatomic particles.

Atoms consist of a nucleus containing protons and neutrons, surrounded by electrons in orbitals.

What is the relative mass of protons, neutrons, and electrons?

Protons and neutrons have approximately equal mass, while electrons have much less mass.

What are the charges of protons, neutrons, and electrons?

Protons are positively charged, neutrons are neutral, and electrons are negatively charged.

How does the number of protons define an element?

The number of protons in the nucleus of an atom determines the element's identity.

What is atomic number and where is it found?

Atomic number is the number of protons in an atom, found on the periodic table.

How can you identify mass number, atomic number, and number of protons from an atomic symbol?

The mass number is the upper left number, atomic number is the lower left number, and the number of protons equals the atomic number.

What is the definition of mass number?

Mass number is the total number of protons and neutrons in an atom's nucleus.

What is an isotope? Provide an example.

Isotopes are atoms of the same element with different numbers of neutrons; for example, Carbon-12 and Carbon-14.

What is atomic mass and how is it calculated?

Atomic mass is the weighted average of the masses of an element's isotopes based on their natural abundance.

What does amu stand for?

Atomic mass unit, the standard unit for measuring atomic mass.

What is the difference between mass number, atomic number, and atomic mass?

Mass number is the sum of protons and neutrons, atomic number is the number of protons, and atomic mass is the weighted average mass of an element's isotopes.

How do you determine if a chemical formula represents a molecular or ionic compound?

Molecular compounds consist of nonmetals and use covalent bonds, while ionic compounds consist of metals and nonmetals and use ionic bonds.

What are cations and anions? How are they formed?

Cations are positively charged ions formed by losing electrons; anions are negatively charged ions formed by gaining electrons.

How do you name molecular compounds?

Use prefixes to indicate the number of atoms of each element in the compound.

How do you name simple ionic compounds?

Ionic compounds are named by stating the metal first followed by the nonmetal with an -ide suffix, without using prefixes.

What is the Roman numeral method for naming ionic compounds with variable charge?

Use Roman numerals to indicate the charge of the metal ion in the compound.

What are polyatomic ions?

Ions composed of two or more atoms that are covalently bonded and carry a charge.

How do you name hydrate molecules?

Name the ionic compound followed by a prefix indicating the number of water molecules, ending with 'hydrate'.