O7s Flashcards
Define Atomic Number?
Atomic number is the number of protons.
Define Mass Number?
Mass number is the number of protons and neutrons.
Define a Mole?
A mole is 6 x 10^23, Avogadro’s number.
What is the shape of the s orbital?
Sphere.
What is the shape of a p orbital?
Dumbbell.
Define an Ion?
An ion is an atom that has lost or gained an electron.
Write the electronic configuration (s,p) for a specific element.
(This would be specific to the element, e.g. for Oxygen: 1s² 2s² 2p⁴).
Define Isotopes?
Isotopes have the same atomic number but different mass numbers.
What are Allotropes?
Allotropes are different physical forms of the same element, differing in the way they are bonded.
Define Amphoteric?
An amphoteric substance can act as both an acid and a base.
Define Relative Atomic Mass?
Relative atomic mass is the average mass of an atom of an element compared to one twelfth the mass of C-12.
Define Electronegativity?
Electronegativity is the attraction that an atom has for a shared pair of electrons in a covalent bond.
Define Ionisation Energy?
Ionisation energy is the energy required to remove the most loosely bound electron from a neutral gaseous atom.
Why does atomic radii decrease across a period?
Atomic radii decrease across a period due to increasing nuclear charge.
Why does atomic radii increase down a group?
Atomic radii increase down a group due to increased shielding or screening.
Define Principle Quantum Number?
The principle quantum number indicates the main energy level of an electron.
Define Subsidiary Quantum Number?
The subsidiary quantum number gives the sublevel energy of an electron.
Define Magnetic Quantum Number?
The magnetic quantum number gives the direction of the orbital.
Define Spin Quantum Number?
The spin quantum number indicates the spin of the electron (+ or -).
Define Catalyst?
A catalyst alters the rate of a reaction without being used up.
Define Dipole Moment?
A dipole moment occurs when the centres of charge do not coincide, resulting in an asymmetrical distribution.
Define No Dipole Moment?
No dipole moment occurs when the centres of charge coincide, resulting in a symmetrical distribution.
Write the equation E2 - E1 = hf.
E2 is the energy at the higher energy level (excited state), E1 is the energy at the ground state, h is Planck’s constant, and f is the frequency of the photon.
Define Transition Elements?
Transition elements have variable valency, are good catalysts, form coloured compounds, and have a partially filled d subshell.
Define Strong Acid?
A strong acid is a good proton donor and is fully dissociated.
Define Weak Acid?
A weak acid is a poor proton donor and is slightly dissociated.
Define Strong Base?
A strong base is a proton acceptor.
Define Weak Base?
A weak base is a poor proton acceptor.
Define Conjugate Base?
A conjugate base is formed when a proton is removed.
Define Conjugate Acid?
A conjugate acid is formed when a proton is added.
Define pH?
pH is defined as -log₁₀[H⁺].
Indicators used in acid-base titrations.
Methyl orange (for strong acid vs. weak base), Phenolphthalein (for weak acid vs. strong base).
Example of an Acidic Oxide?
Carbon Dioxide.
Example of an Amphoteric Acid?
Water.
Define Electronegativity (again)?
Electronegativity is the relative measure of attraction for a shared pair of electrons in a covalent bond.
Define Binary Compound?
A binary compound is made up of two elements.
Types of Bonds?
Ionic, covalent, and polar covalent.
Flame test: Potassium?
Purple/Lilac.
Flame test: Sodium?
Yellow/Orange.
Flame test: Lithium?
Red/Crimson.
Flame test: Strontium?
Red.
Flame test: Copper?
Green.
Flame test: Barium?
Green.
Why does sodium chloride conduct electricity in solution but not in a solid state?
Sodium chloride conducts electricity in solution because ions are free to move.
Define Valency?
Valency is the number of electrons an atom of an element gives, takes, or shares when bonding.
How to calculate the percentage element in a compound?
(Mass of element in the compound / Total mass of compound) x 100.
Define Heat of Solution?
Heat of solution is the heat or energy involved when one mole of a substance is dissolved in excess water.
Define Heat Change in a reaction?
Heat change refers to the energy change when the number of moles indicated in the balanced chemical equation reacts completely.
Define Heat of Combustion?
Heat of combustion is the heat change when one mole of a substance is burned in excess oxygen.
Define Heat of Formation?
Heat of formation is the heat change when one mole of a substance is formed from its elements in their standard state.
Define Exothermic Reaction?
An exothermic reaction gives out heat or energy.
Define Endothermic Reaction?
An endothermic reaction absorbs heat or energy.
Shape of BF₃?
Triangular planar (120°).
Shape of CO₂?
Linear (180°).
Shape of H₂S?
V-shaped (104.5°).
Shape of H₂O?
V-shaped (104.5°).
Shape of CH₄?
Tetrahedral (109.5°).
