Elements of life Flashcards
What are the subatomic particles in an atom and their charges?
Protons (+1), Neutrons (0), Electrons (-1).
What is the relative mass of protons, neutrons, and electrons?
Protons and neutrons: 1, Electrons: 0.0005.
What is the notation for an atom in terms of A, Z, and X?
A = Mass number, Z = Atomic number, X = Element symbol.
What is Avogadro’s constant?
6.02 × 10²³ mol⁻¹.
What are isotopes?
Atoms of the same element with different numbers of neutrons.
What is the difference between cations and anions?
Cations are positively charged ions; anions are negatively charged ions.
What is relative atomic mass (Ar)?
The mean relative mass of an atom compared to 1/12th of a carbon-12 atom.
What is the equation for calculating moles from mass?
n = m / M, where n is moles, m is mass (g), and M is molar mass (g mol⁻¹).
What is the molecular formula?
The actual number of atoms of each element in a molecule.
What is the empirical formula?
The simplest whole-number ratio of atoms of each element in a compound.
What is the formula for percentage yield?
Percentage yield = (Actual yield / Theoretical yield) × 100.
What is water of crystallisation?
Water molecules embedded in a crystal structure.
What is the formula for concentration in a solution?
n = c × V, where n is moles, c is concentration (mol dm⁻³), and V is volume (dm³).
What is the use of a volumetric pipette?
To accurately measure a fixed volume of liquid.
What is the use of a burette in titrations?
To dispense a solution and record its volume accurately.
What is a standard solution?
A solution of known concentration.
What is the equation for the first ionisation energy?
X(g) → X⁺(g) + e⁻.
What is Hess’s law?
The enthalpy change of a reaction is independent of the path taken.
What are sub-shells in electron configuration?
Divisions within electron shells, e.g., s, p, d, and f.
What is the maximum number of electrons in the s, p, d, and f sub-shells?
s: 2, p: 6, d: 10, f: 14.
What is the electronic configuration of sodium?
1s²2s²2p⁶3s¹.
What is covalent bonding?
The sharing of electrons between two non-metal atoms.
What is ionic bonding?
The transfer of electrons between a metal and a non-metal to form oppositely charged ions.
What is metallic bonding?
The attraction between positive metal ions and a sea of delocalised electrons.
What is the periodic trend for ionisation energy across a period?
Ionisation energy increases due to increasing nuclear charge and constant shielding.
What is the trend in melting points across periods 2 and 3?
Melting points increase up to group 4, then decrease.
What is nuclear fusion?
The process where two light atomic nuclei combine to form a heavier nucleus, releasing energy.
What is the principle behind emission spectra?
Electrons absorb energy to jump to higher levels and emit photons when returning to lower levels.
What are the flame test colours for common ions?
Li⁺: Bright red, Na⁺: Yellow, K⁺: Lilac, Ca²⁺: Dark red, Ba²⁺: Green, Cu²⁺: Blue-green.
What is the equation for wave speed?
c = λ × ν, where c is wave speed, λ is wavelength, and ν is frequency.
What is the formula for calculating relative atomic mass from a mass spectrum?
Relative atomic mass = (Σ(relative isotopic mass × abundance)) / 100.
What is a salt?
A compound formed when the hydrogen in an acid is replaced by a metal or ammonium ion.
What is the general reaction for acids and carbonates?
Acid + Carbonate → Salt + Water + Carbon Dioxide.
What is a precipitation reaction?
A reaction where an insoluble solid (precipitate) forms in solution.
What is the test for ammonium ions (NH₄⁺)?
Add sodium hydroxide and heat; test for ammonia gas with damp red litmus paper, which turns blue.
What is the test for halides (Cl⁻, Br⁻, I⁻)?
Add nitric acid and silver nitrate: Cl⁻ forms white precipitate, Br⁻ cream, I⁻ yellow.
What is the trend in solubility of group 2 hydroxides?
Solubility increases down the group.
What are group 2 carbonates?
Compounds with the formula MCO₃ that decompose into metal oxides and CO₂ upon heating.
What is charge density?
The concentration of charge on a cation, affected by ionic size and charge.
What is Bohr’s model of the atom?
Electrons orbit the nucleus in fixed energy levels, with energy levels converging at higher values.
What are the periodic table groups?
Columns of elements with the same number of outer shell electrons.
What is the importance of the periodic table periods?
Rows that indicate the number of electron shells in elements.
What are noble gases?
Unreactive elements in group 18 with full outer electron shells.
