Structure 1: Models of the Particulate Nature of Matter

Flashcards covering introductory chemistry concepts including the particulate nature of matter, atomic structure, isotopes, electron configurations, stoichiometry, and gas laws.

How are elements defined in the context of the particulate nature of matter?

Elements are the primary constituents of matter that cannot be chemically broken down into simpler substances.

What is the distinction between a compound and a mixture?

Compounds consist of atoms of different elements chemically bonded together in a fixed ratio, whereas mixtures contain more than one element or compound in no fixed ratio that are not chemically bonded.

What are the characteristics of a homogeneous mixture?

A homogeneous mixture has a uniform composition with no visible boundaries, meaning components are equally distributed and in the same state throughout.

Which separation method uses a porous material to separate solid particles from a liquid based on particle size?

Filtration.

How does the Atomic Theory describe the behavior of atoms in chemical reactions?

Atoms cannot be created nor destroyed; however, they are rearranged in chemical reactions.

According to the Kinetic Molecular Theory (KMT), how is the amount of kinetic energy related to temperature?

The amount of kinetic energy is proportional to the absolute temperature of the substance, with greater motion at higher temperatures and lesser motion at lower temperatures.

What is absolute zero in both Kelvin and Celsius scales?

Absolute zero is $0\,K$ or $-273\,^{\circ}C$, which is the point where all particles stop moving.

What is the formula for calculating density ($d$)?

$$d = \frac{m}{V}$$

What are the three subatomic particles and their respective relative charges and masses?

Proton: charge $+1$, mass $1$; Neutron: charge $0$, mass $1$; Electron: charge $-1$, mass negligible ($5 \times 10^{-4}$).

What does the atomic number (symbol $Z$) represent?

The number of protons in the nucleus of an atom.

Define the term 'isotopes'.

Atoms of the same element that have the same atomic number ($Z$) but a different mass number ($A$) due to varying numbers of neutrons.

What is the definition of relative atomic mass ($A_r$)?

The weighted average mass of an atom compared to $\frac{1}{12}$ the mass of an atom of carbon-12.

What is the function of a mass spectrometer?

It is a device used to determine the relative atomic masses of an atom and identify the number of isotopes in an element.

How are frequency ($f$) and wavelength ($\lambda$) related to the energy of electromagnetic radiation?

Energy is directly proportional to frequency and inversely proportional to wavelength.

What is the difference between a continuous spectrum and a line spectrum?

A continuous spectrum shows all wavelengths or frequencies of visible light (like a rainbow), whereas a line spectrum shows only specific frequencies unique to an element.

What are the two components of Bohr's theory regarding electron energy levels?

Electrons exist in principal energy levels (shells) and can move between them by absorbing or emitting energy; they cannot exist between these defined levels.

What is the maximum number of electrons that can occupy a main energy level ($n$)?

$$2n^2$$

Define an 'atomic orbital'.

A region in space where there is a high probability of finding an electron, capable of holding a maximum of two electrons.

What are the shapes of the 's' and 'p' orbitals?

The 's' orbital is spherical, and 'p' orbitals are dumbbell-shaped.

What does the Aufbau principle state?

Electrons fill atomic orbitals of the lowest energy levels first.

What are the specific electron configuration exceptions required by the IB?

Chromium ($Cr$) and Copper ($Cu$).

What is the value of the Avogadro constant ($N_A$)?

$$6.02 \times 10^{23}\,mol^{-1}$$

Define the term 'molar mass' ($M$) and state its unit.

Molar mass is the mass of one mole of a substance, expressed in units of $g\,mol^{-1}$.

What is the difference between an empirical formula and a molecular formula?

An empirical formula is the simplest whole-number ratio of atoms in a compound, while the molecular formula shows the actual number of atoms of each element in a molecule.

Define molar concentration and state its common units.

The amount (in $mol$) of solute per volume (in $dm^3$) of solution, usually expressed as $mol\,dm^{-3}$ or $M$.

What is the dilution formula used to find the new concentration after adding solvent?

$$C_1 V_1 = C_2 V_2$$

What is a standard solution?

A solution with an accurately known concentration.

What are the key assumptions of the ideal gas model regarding particles and collisions?

Particles have negligible volume, there are no intermolecular forces of attraction, and all collisions are perfectly elastic (no energy loss).

What is the molar volume of an ideal gas at STP ($273\,K$, $100\,kPa$)?

$$22.7\,dm^3\,mol^{-1}$$

Under what specific conditions do real gases deviate most from ideal behavior?

Low temperature and high pressure.

What is the Ideal Gas Equation?

$$PV = nRT$$