Chemistry - Chapter Two

Who proposed the indivisible atom theory?

John Dalton

Which experiment discovered the electron?

J.J. Thomson's Cathode Ray Tube Experiment

Which experiment determined the charge of an electron?

Robert Millikan's Oil Drop Experiment

What model of the atom did Thomson propose?

Plum pudding model

What was the significance of Rutherford's gold foil experiment?

"It showed atoms have a dense, positively charged nucleus

Where are protons and neutrons located?

In the nucleus

Where are electrons located in an atom?

Orbiting around the nucleus

What is the relative mass and charge of a proton?

Mass = 1.0073 amu; Charge = +1

What is the relative mass and charge of a neutron?

Mass = 1.0087 amu; Charge = 0

What is the relative mass and charge of an electron?

Mass = 0.00055 amu; Charge = -1

What does the atomic number (Z) represent?

The number of protons in an atom

How is mass number (A) calculated?

A = number of protons + number of neutrons

What is an isotope?

Atoms of the same element with different numbers of neutrons

What is an ion?

An atom that has gained or lost electrons and has a charge

What is a cation?

An atom that loses electrons and has a positive charge

What is an anion?

An atom that gains electrons and has a negative charge

What is the atomic mass unit (amu)?

1 amu = 1.6605 × 10⁻²⁴ g

How is average atomic mass calculated?

"By averaging the masses of all naturally occurring isotopes, weighted by their abundance"

What tool is used to determine isotopic masses and abundances?

Mass spectrometer

What is a mole?

An amount unit representing 6.022 × 10²³ particles

What is Avogadro's number?

6.022 × 10²³ particles/mol

What are 'particles' in chemistry?

Atoms, molecules, or formula units depending on the substance type

What is molar mass?

The mass of 1 mole of a substance in grams

How is molar mass related to atomic mass?

"They are numerically equal but molar mass is in g/mol and atomic mass is in amu"

How many atoms are in 1 mol of carbon?

6.022 × 10²³ atoms

How do you calculate moles from mass?

moles = mass (g) / molar mass (g/mol)

How do you calculate number of atoms from mass?

"Use moles = mass / molar mass then multiply by Avogadro's number"

What is the formula mass?

Sum of atomic masses in a formula unit for ionic compounds

What is the molecular mass?

Sum of atomic masses in a molecule for covalent compounds

Who developed the first periodic table based on atomic mass?

Dmitri Mendeleev

How are elements arranged in the modern periodic table?

By increasing atomic number

What are periods in the periodic table?

Horizontal rows

What are groups in the periodic table?

Vertical columns

What are the main classifications of elements?

"Metals nonmetals, and metalloids"

Which groups are main group elements?

Groups 1-2 and 13-18

What are alkali metals?

Group 1 elements (except hydrogen)

What are alkaline earth metals?

Group 2 elements

What are halogens?

Group 17 elements

What are noble gases?

Group 18 elements