Particulate Nature Of Matter And Structure Of The Atom Flashcards
What is the dilution law?
It is the number of times a more concentrated solution is diluted to obtain a less concentrated solution
What is an atom?
The smallest particle of an element which can take part in a chemical reaction and retain its chemical properties
What is a molecule?
A chemically combined group of atoms which can take part in a chemical reaction and retain its original purpose
Define atomicity
The number of replaceable hydrogen ions in a compound
What is an ion?
An electrically charged atom formed by the loss or gain of one or more electrons
State 3 evidences of the Particulate Nature of Matter
Brownian motion
Osmosis
Crystallization
Diffusion
State 5 postulates of Dalton
Hint: TIDY AC
Tiny indivisible particles called atoms
Identical masses and sizes for the same element
Different elements have different masses and sizes
You can’t destroy or create atoms
Atoms combine is small whole number ratios
State 3 limitations of Dalton
Atoms are divisible into sub atomic particles what are protons, electrons and neutrons
Atoms can be physically destroyed or created in a chemical/nuclear fission or fussion reaction
Atoms of the same element can be different if they are isotopes
Describe Democritus’ theory of atoms.
Democritus proposed that all matter in the universe was made of tiny, indivisible solid objects called ‘atomos’.
What is the particulate nature of matter?
The particulate nature of matter is the idea that matter is made up of tiny particles such as atoms, molecules, or ions.
Explain the spread of potassium tetraoxomanganate (VII) crystals in water.
When a few crystals of KMnO4 are introduced into water, they fall apart and spread throughout the water, resulting in a uniform distribution of colored KMnO4.
How does ammonia gas spread in a laboratory?
Ammonia gas, or any strong perfume or substance with a strong scent, spreads among air particles to other parts of the laboratory.
What is crystallization and how does it provide evidence for the particulate nature of matter?
Crystallization is the process of forming a solid/crystal by combining millions of particles from a solution, demonstrating that matter consists of particles.
Define Brownian motion.
Brownian motion is the random movement of a speck of a solid on the surface of a liquid due to the random movement of the particles of the fluid.
Describe an atom.
An atom is the smallest particle of an element that can take part in a chemical reaction.
Define a molecule.
A molecule is the smallest, stable particle of an element or compound that consists of a single atom or a group of two or more atoms chemically combined.
What is the atomicity of calcium?
Calcium is monoatomic, meaning it consists of only one atom.
Describe a compound.
A compound is a substance that is formed from the chemical combination of atoms of two or more different elements in a fixed ratio or proportion.
What is the difference between a homogeneous and heterogeneous mixture?
A homogeneous mixture is uniform in composition throughout and normally in the same physical state, while a heterogeneous mixture’s composition is not uniform and may exist in different states.
Do noble gases exist as monoatomic or diatomic molecules?
Noble gases exist as monoatomic molecules.
Define an ion.
An ion is an electrically charged particle formed from an atom or compound by gaining or losing one or more electrons.
Describe a polyatomic ion.
A polyatomic ion is a group of bonded atoms with a charge.
What is the atomicity of oxygen molecule?
The atomicity of an oxygen molecule (O2) is diatomic, meaning it consists of two atoms.
Describe Dalton’s atomic theory.
Dal’s atomic theory proposed that matter is made up of small indivisible particles called atoms, which cannot be created or destroyed. Atoms of the same element are identical in size and mass, while atoms of different elements have different mass and size. Atoms combine to form compounds in simple whole numbers.
What is the law of conservation of mass?
The law of conservation of mass states that the mass of the starting materials in a chemical reaction is always equal to the mass of the ending materials.
Define alloys.
Alloys are mixtures of two or more metals, such as steel, that have properties different from those of the individual metals.
How do gas-gas mixtures differ from solid-liquid mixtures?
Gas-gas mixtures, like air, consist of gases uniformly mixed together, while solid-liquid mixtures, like salt solution, water, and sand, contain solid particles dispersed in a liquid.
What did Antoine Lavoisier observe in his experiments with metals?
Antoine Lavoisier observed that the mass of the starting materials in a reaction was always equal to the mass of the ending materials, leading to the law of conservation of mass.
Describe the law of definite proportions.
The law of definite proportions states that elements react in the same proportions by mass in every chemical reaction. For example, hydrogen and nitrogen react in a fixed ratio of 1:4.7 or 2:9.4.
What are sub-atomic particles?
Sub-atomic particles are smaller, more fundamental particles that make up atoms. Examples include protons, neutrons, and electrons
Why is Dalton’s theory of atoms considered incorrect?
Dalton’s theory is considered incorrect because it proposed that atoms are indivisible, when in fact they are composed of sub-atomic particles. Additionally, atoms can be created and destroyed in nuclear reactions.
Describe J.J. Thompson’s experiment to discover electrons.
J.J. Thompson used a cathode ray tube to observe cathode rays, which were deflected by electric and magnetic fields, indicating they were charged particles. He also found that the rays moved straight through the hole in the anode and were detected as a glow on a fluorescent screen.
What deductions did Thompson make from his observations of cathode rays?
Thompson deduced that the cathode rays were electric carriers, negatively charged, and present in all types of matter.
Define isotopes.
Isotopes are atoms of the same element that differ in mass and size.
How did Thompson describe the structure of an atom in his ‘plum pudding’ model?
Thompson proposed that an atom is a solid sphere of positive charge with negative electrons stuck uniformly in it, balancing the positive charges to make the atom neutral.
What is the charge to mass ratio of electrons according to Thompson’s measurements?
Thompson found that the charge to mass ratio of electrons is -1.7 × 10^8 C/g for all matter.
Do cathode rays behave differently when different gases, materials of the tube, and electrodes are changed?
No, cathode rays behave the same way regardless of the gases, materials of the tube, and electrodes used.
Describe Rutherford’s alpha particle scattering experiment.
Lord Rutherford bombarded thin foils of gold and other metals with alpha particles and observed that most of the particles passed through the foil without deviation, while a few were deflected through small and large angles, and very few bounced back.
What are alpha particles?
Alpha particles are ionized helium atoms emitted by radioactive substances or elements. They are heavier than electrons and easily ionize other particles.
