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Vocabulary flashcards for Year 11 Chemistry.
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Who was J.J. Thomson and what did he discover?
Joseph John Thomson was a British physicist who won the Nobel Prize in 1906. He discovered the electron and proposed the plum pudding model of the atom.
Thomson's cathode-ray tube experiment led him to conclude that _ were present in all types of matter.
electrons
What did Rutherford contribute to atomic theory?
Rutherford discovered that atoms have a small, dense, positively charged center (nucleus) with electrons moving around the outside.
What is the plum pudding model?
Thomson's model of the atom where electrons (like plums) are embedded in a positively charged sphere (like pudding).
According to Schrödinger, electrons exist in _.
shells
What subatomic particle did Chadwick discover?
The neutron
Fill in the missing information: Proton: Location = ?, Charge = +1, Mass = 1 Neutron: Location = Nucleus, Charge = ?, Mass = 1 Electron: Location = ?, Charge = -1, Mass = ?
Proton: Location = Nucleus Neutron: Charge = 0 Electron: Location = Rapidly moving around the nucleus, Mass = 1/1836
Calculate the number of neutrons in Sodium (Na) if atomic number = 11 and mass number = 23.
Neutrons = Mass number - Atomic number = 23 - 11 = 12 neutrons
The formula for calculating neutrons is: Neutrons = -
Mass number - Atomic number (or protons)
What determines the identity of an atom?
The number of protons (atomic number) determines the identity of an atom.
What is analytical chemistry?
Analytical chemistry involves the use of techniques to obtain information about chemical substances.
_______ analysis is the identification of elements or compounds present in a sample, while _______ analysis determines the amounts
Qualitative; Quantitative
Name 3 techniques used in quantitative analysis.
Any 3 of: Atomic Absorption Spectroscopy, UV-visible spectroscopy, infrared spectroscopy, chromatography, nuclear magnetic resonance, mass spectroscopy
What are flame tests an example of?
Emission spectroscopy
Normally atoms are in the " _ state" where electrons are in the lowest possible energy level.
ground
What happens when atoms absorb energy?
Electrons jump to higher energy levels, creating an "excited state" which is unstable. Electrons quickly return to ground state, releasing energy as light.
What is an absorption spectrum?
A series of dark lines superimposed on a continuous spectrum, showing wavelengths of light that have been absorbed.
What is an emission spectrum?
A series of bright lines against a black background, showing wavelengths of light that have been emitted.
Match the metal ion with its flame color: Sr²⁺, K⁺, Na⁺, Ba²⁺, Cu²⁺ Colors: Red, Orange, Yellow, Green, Pinkish orange
Sr²⁺ = Red, K⁺ = Pinkish orange, Na⁺ = Orange, Ba²⁺ = Yellow, Cu²⁺ = Green
What is AAS used for in industry?
Monitoring the purity of substances (air, water, food), measuring metal ion concentrations at trace levels (ppm or ppb).
In AAS, the higher the concentration of metal in the sample, the _ the absorption.
greater
List the 6 steps for using AAS.
Choose correct lamp for the metal, 2. Make standards with known concentrations, 3. Test standards and record absorbance, 4. Draw calibration curve (concentration vs absorbance), 5. Test unknowns and record absorbance, 6. Use calibration curve to determine concentration
What does the nebulizer do in AAS?
Sucks up samples at controlled rate, creates fine aerosol spray, and mixes aerosol with fuel and oxidant for introduction into flame.
What is the function of the monochromator in AAS?
Separates thousands of lines to select the specific wavelength absorbed by the sample and exclude other wavelengths.
What is mass spectrometry used for?
An instrument to separate particles with different masses and determine relative proportions of particles in a mixture.
Name 4 uses of mass spectrometry.
Find composition of mixtures, 2. Determine molecular structures, 3. Find isotopic composition and atomic mass, 4. Detect impurities/viruses
What are the 4 main steps in mass spectrometry?
Ionization (knock off electrons to create positive ions), 2. Acceleration (same kinetic energy), 3. Deflection (by magnetic field based on mass), 4. Detection (electrical detection)
In mass spectrometry, lighter ions are deflected _ than heavier ions.
more
Calculate the relative atomic mass of Bromine using MS data: ⁷⁹Br (50% abundance) and ⁸¹Br (50% abundance).
Mr(Br) = ((79×50) + (81×50))/100 = 80
What is atomic radius?
The size of an atom, including the nucleus, electrons, and all empty space in the atom.
Atomic radius depends on 3 things: number of ____, position of electrons in_____ , and ____on nucleus.
electrons; shells; charge
How does atomic radius change down a group and across a period?
Down a group: increases (more electron shells); Across a period: decreases (stronger nuclear attraction)
What is electronegativity?
An atom's ability/attraction to electrons.
____is the most electronegative atom, and ______ is the least electronegative.
Fluorine; Francium
How does electronegativity change down a group and across a period?
Down a group: decreases (outer electrons further from nucleus); Across a period: increases (stronger nuclear attraction)
What is ionization energy?
The amount of energy needed to remove an electron from an atom.
Low ionization energy means it's____ to remove an electron, while high ionization energy means it's _____to remove an electron.
easy; hard
How does ionization energy change down a group and across a period?
Down a group: decreases (weaker attraction); Across a period: increases (stronger nuclear attraction)
Why do successive ionization energies increase for the same atom?
Each electron is being removed from an increasingly positive ion, and there's a large jump when removing from a shell closer to the nucleus.
What is electron affinity?
The energy change when an atom gains electrons; the ability of an atom in gaseous state to accept an electron.
What is metallic bonding?
The electrostatic attraction between positive metal cations and delocalised electrons in a 3D lattice.
Metallic bonding occurs between _ atoms only.
metal
Name 5 properties of metallic bonding and explain one.
Conduct heat/electricity, 2. Hardness, 3. Malleability/ductility, 4. High melting/boiling points, 5. Lustre.
What is ionic bonding?
Electrostatic attraction between oppositely charged ions arranged in a 3D lattice, formed between metal and non-metal.
In ionic bonding, metals electrons to become , while non-metals electrons to become .
lose; cations; gain; anions
Why are ionic compounds hard but brittle?
Hard due to strong attraction between ions; brittle because when layers slide, like charges repel causing shattering.
Why don't ionic solids conduct electricity, but ionic liquids do?
Solids have fixed ion positions (can't move), but in liquids/solutions ions are free to move and carry charge.
What is covalent bonding?
Electrostatic attraction between positive nuclei and shared pair(s) of electrons, formed between non-metals.
A single covalent bond involves shared electrons, a double bond involves , and a triple bond involves _.
2 (1 pair); 4 (2 pairs); 6 (3 pairs)
Compare melting points: covalent molecular vs covalent network.
Covalent molecular: Low (weak intermolecular forces); Covalent network: Very high (must break strong covalent bonds)
Why is graphite a conductor but diamond isn't?
Graphite has delocalised electrons (4th electron per carbon) free to move between layers; diamond has all electrons in covalent bonds.
What are some examples of network covalent substances?
Diamond, graphite, carbon (as graphite or diamond), carbon dioxide, silicon, boron, silicon carbide, and silicon nitride.
What steps should you follow when justifying bonding properties?
Type of bond, 2. Lattice type, 3. Intermolecular forces, 4. Nuclear attraction, 5. Delocalised electrons, 6. Bond definition, 7. Directional bonds, 8. Property explanation
Justify why silver is malleable.
Silver has metallic bonding with delocalised electrons in a "sea" around cations in 3D lattice. Strong electrostatic attraction forms non-directional bonds. Layers can slide past each other while maintaining the metallic lattice due to non-directional bonding.
Justify why diamond is very hard.
Diamond is a covalent network with each carbon covalently bonded to 4 others in 3D lattice. Strong intramolecular forces (covalent bonds) require lots of energy to disrupt and break apart.
What size range defines nanomaterials?
1nm to 999nm
Name 4 properties of nanoparticles.
High elasticity, high thermal conductivity, low density, chemically more inert
Name 3 uses of nanotechnology.
Drug delivery, sensing, water treatment
Name 3 environmental concerns about nanoparticles.
Can accumulate for long periods, move up food chain, harm ecosystems, alter microbial processes, leach into water/soil
What are hydrocarbons?
Organic compounds containing only carbon and hydrogen atoms.
Carbon has electrons in outer shell and needs to form bonds to be stable.
4; 4
Define empirical, molecular, and structural formulas.
Empirical: smallest whole number ratio; Molecular: actual ratio; Structural: arrangement of atoms (drawn)
What are the two main types of hydrocarbons?
Aromatic (contain benzene rings) and Aliphatic (no benzene rings)
What is benzene and how is it represented?
C₆H₆, most important aromatic hydrocarbon, represented as hexagon with circle inside showing 6 delocalised electrons
What is the general formula for alkanes?
CnH₂n+₂
What makes alkanes "saturated"?
They contain only single bonds between carbon atoms.
Give the prefixes for 1-8 carbons.
1=meth, 2=eth, 3=prop, 4=but, 5=pent, 6=hex, 7=hept, 8=oct
What makes alkenes "unsaturated"?
They contain at least one double bond between carbon atoms.
Name the alkyl groups: CH₃-, CH₂CH₃-, CH₂CH₂CH₃-
Methyl, Ethyl, Propyl
Give the prefixes for: Fluorine, Chlorine, Bromine, Iodine
Fluoro, Chloro, Bromo, Iodo
Name 3 general properties of hydrocarbons.
Low melting/boiling points, colourless, often no odor (simple ones)
What is the formula for cycloalkanes and cycloalkenes?
Cycloalkanes: CnH₂n ; Cycloalkenes: CnH₂n-₂
What are the products of complete vs incomplete combustion?
Complete: CO₂ + H₂O; Incomplete: CO + H₂O
Carbon monoxide is ______ and _______.
colourless; odourless
What is an exothermic reaction?
A reaction that releases heat energy to surroundings, temperature increases, energy released > energy required, ΔH is negative.
What is an endothermic reaction?
A reaction that takes in heat from surroundings, temperature decreases, energy required > energy released, ΔH is positive.
Breaking bonds ____energy, while forming bonds______ energy.
takes/requires; releases
State the law of conservation of energy.
Energy cannot be created or destroyed, only transferred. All energy lost or gained must go or come from somewhere.
How can you tell if a reaction is exothermic or endothermic from an energy diagram?
Exothermic: products lower than reactants (energy released); Endothermic: products higher than reactants (energy absorbed)
In the equation: A + B → C + D + 150kJ, is this exothermic or endothermic?
Exothermic (heat is a product, energy released)
Complete the trend summary: Atomic radius: ↑ down, ↓ across Electronegativity: ↓ down, ↑ Ionization energy: ↓ , ↑ across
across; down
Match bonding type with conductivity: Metallic, Ionic solid, Ionic liquid, Covalent molecular, Covalent network Options: Conductor, Non-conductor
Metallic: Conductor; Ionic solid: Non-conductor; Ionic liquid: Conductor; Covalent molecular: Non-conductor; Covalent network: Non-conductor (except graphite)
Why are Group 1 & 2 metal compounds usually white/colorless while transition metal compounds are colored?
Group 1 & 2 metals form simple ionic compounds, while transition metals have partially filled d-orbitals that can absorb visible light.
Name one technique each for qualitative and quantitative analysis.
Qualitative: Flame tests; Quantitative: Atomic Absorption Spectroscopy (AAS)
What information can mass spectrometry provide about bromine isotopes?
The relative abundance of ⁷⁹Br and ⁸¹Br isotopes, allowing calculation of average atomic mass (≈80 amu).