Chlem Tzayle Flashcards
(15 cards)
What is the Particle Theory of Matter?
All matter is made up of tiny particles that are always moving and attract each other. Higher temperature results in faster particle movement, and there is space between particles.
What are the classifications of matter?
Matter can be classified as Pure Substances (elements, compounds) or Mixtures (homogeneous, heterogeneous).
Examples: Water (compound), Air (homogeneous mixture), Sand + Water (heterogeneous mixture).
What are independent and dependent variables?
Independent Variable: The factor you change (e.g., temperature in an experiment). Dependent Variable: The factor you measure (e.g., reaction rate). Control Group: Stays constant for comparison.
Example: In the penny lab, water amount = independent variable; # of drops = dependent variable.
What are the physical properties of matter?
Physical properties can be qualitative (observed, e.g., color, texture) or quantitative (measured, e.g., mass, volume).
Examples: Combustibility (chemical property), Reactivity (chemical property).
What are chemical properties of matter?
Chemical properties describe how a substance reacts, such as flammability and acidity.
Example: Reactivity with iodine – iodine turns starch purple.
What is the formula for density?
Density = Mass ÷ Volume (D = m/v). Units are g/cm³ or kg/m³.
Example: Given: Mass = 10 g, Volume = 2 cm³. Required: Density. Answer: D = 10 ÷ 2 = 5 g/cm³.
What is the difference between physical and chemical changes?
A physical change does not create a new substance (e.g., melting ice), while a chemical change results in a new substance (e.g., rusting iron). Clues include color change, gas production, and heat/light.
What are periods and groups in the periodic table?
Periods are horizontal rows, and groups are vertical columns that share similar properties. Roman numerals indicate the number of valence electrons.
What are the characteristics of metals, non-metals, and metalloids?
Metals are conductive, malleable, shiny, and lose electrons. Non-metals are poor conductors, brittle, dull, and gain electrons. Metalloids have properties of both (e.g., Silicon).
What are some exceptions on the periodic table?
Examples include Hydrogen (not a metal but in Group 1) and Helium (noble gas with 2 electrons).
What are the atomic theories proposed by Dalton, Thomson, Rutherford, and Bohr?
Dalton: Atoms are indivisible particles. Thomson: Plum pudding model (electrons in positive sphere). Rutherford: Nucleus is dense and positive, surrounded by electrons. Bohr: Electrons in fixed orbits/shells.
What are the subatomic particles?
Protons have a positive charge and are in the nucleus. Neutrons are neutral and also in the nucleus. Electrons have a negative charge and are in orbitals.
Example: Carbon-12 → Protons: 6, Neutrons: 6, Electrons: 6.
What are the steps to draw Bohr-Rutherford diagrams?
- Draw the nucleus with the number of protons and neutrons. 2. Draw shells with electrons (2, 8, 8, etc.).
Example: Sodium (Na): 11 protons, 12 neutrons, 11 electrons.
What are the trends along periods and groups in the periodic table?
Across periods, electronegativity and ionization energy increase. Down groups, atomic size and metallic character increase.
What are the tests for gases?
Oxygen relights a glowing splint. Hydrogen makes a ‘pop’ sound with a flaming splint. Carbon Dioxide turns limewater cloudy.
