Science Exam Semester 1
Terms in this set (76)
said matter was made of small pieces that COULDN'T be cut into smaller pieces
purposed that all matter is composed of atoms
1897; He found atoms contain negatively charged particles later known as ELECTRONS. (Muffin model) he inferred there must be POSITIVE charge because the over all atom is NEUTRAL
1911; gold foil experiment with nucleus. The positive particle bean was defaced strongly when it hit the center of the atom (like charges repeal) one of Thomson students
1913 he showed that electrons could have only certain amounts of energy leading them to move in certain orbits (planets orbiting the sun)
the number of protons in the nucleus of an atom
atoms with the same number of protons but different number of neutrons
the sum of the protons and neutrons in the nucleus
a Russian scientist that discovered a set of patterns that applied to all the elements
organized by atomic mass have periods vertical and families (groups) horizontal
Modern periodic table
horizontal rows from left to right the properties of the elements change in a PATTERN
vertical rows, 18 of them, also called families, consist of elements with similar characteristics
reading an element square
each square includes the element's atomic number, chemical symbol, name, and atomic mass. symbols are abbreviated for their latin names
How do elements form stars?
nuclear fusion which occurs in stars on a hue scale, combines smaller nuclei into larger nuclei, creating heavier elements
What are physical and chemical properties of metals?
Physical: malleable, ductile, conduct electricity, good conductors, haps, and shiny Chemical: reactive and corrosion
What are the names of the metal families and info about them?
ALAKI - group 1, they react with other elements by losing 1 electron, never found uncombined in nature because they are so reactive, Shiny and soft, 2 most popular sodium and potassium. ALKALINE EARTH METALS- group 2 fairly hard, grayish white, good conductors, react by losing 2 electrons, most common magnesium and calcium
What are physical and chemical properties of nonmetals?
Physical: poor conductors, dull, and brittle Chemical: most nonmetals are reactive except group 18, they rarely react
What are the names of the 6 nonmetal families and info about them?
Carbon: group 14 have 4 valence electrons to share. Nitrogen: group 15 5 valence electrons to share. Oxygen: group 16 6 valence electrons to share. Halogen: group 17 7 valence electrons to share, noble gases; group 18 with full valence electrons. Hydrogen: 1 proton and 1 electron usually found combined with oxygen in water
Characteristics of both metals and nonmetals on the zig zag line
highest energy level (farthest away from the nucleus) held loosely
includes the symbol of the element surrounded by dots. each dot represents a valence electron.
electron dot diagram
How does the periodic table work?
Organized by increasing atomic number, By groups which elements with a group have the same number of valance electrons and across a period the valance electron increases from 1 to 8
Where are the three groups located on the periodic table?
Metals metalloids and nonmetal. Metals; are located at the very left if the periodic table. Metalloids: are on the stair case. Nonmetals: are above the stair case on the right
Are between a metal and nonmetal. Attraction between 2 oppositely charged ions
Are found when 2 or more nonmetals share their valence electrons
How do ions form?
Ions are an atom of group of atoms that were electrically charged
Ions that are made of more than 1 type of atom
Combination of symbols that shows the ratio of elements in a compound
tell u the ratio of elements in a compound (smaller, lower)
Naming of ionic compounds
Positive ion come first fooled by the nonmetal. If the nonmetal is single, it's end names changed to ide. If polyatomic it's name does not change
What are the properties of ionic compounds?
Ionic crystals, high melting point, and electrical conductivity
The chemical bond formed when 2 or more nonmetals share their valence electrons
What are the properties of molecular compounds?
Contains atoms that are covalently bonded, low melting points, forces between molecules are much weaker than ionic bonds, and less heat is needed to break the bonds
A covalent bond in which electrons are shared unequally (bully)
A covalent bond in which electrons are shared equally
A mixture made of 2 or more elements that had the properties of metal
An attraction of a positive metal ions and electrons surrounding it
An alloy of iron, carbon, nickel, chromium
Anything that has mass and takes up space
What are the properties of matter?
Can be described in terms of chemical and physical changes
What is the difference between physical and chemical changes?
Physical - any change that changes its appearance but not object Chemical - forms a completely new substance
What are five evidence that a chemical reaction may have
Color change, precipitate, A gas may be produced, light, heat
A reaction in which energy is absorbed
A reaction that releases energy in the form of heat
A short easy way to show a chemical reaction using symbols instead of words
Substances you have at the beginning, always on the left side of arrow
When reaction is complete you have new substances called this, right side of arrow
States that during a chemical reaction matter is not created or destroyed
conservation of mass
Matter can enter from or escape the surrounding
Matter not allowed to enter or leave
How do you balance a chemical equation?
Right equation, count Atoms, use coefficients to balance
A number placed in front of a chemical formula in an equation to balance
What are three classifications of a chemical reaction?
Synthesis, decomposition, replacement
What are five factors that affect the rate of chemical reactions?
Surface area, temperature, concentration, catalyst, inhibitors
What are the three components to make a fire?
Fuel oxygen and heat
Well mixed mixture that contains a solvent and at least one solute
The part of a solution present in the largest amount
The substance that is present in the solution in a smaller amount and is dissolved by the solvent
A mixture containing small undissolved particles that do not settle out and these particles are large enough to scatter in a light beam
A mixture in which the particles can be seen and easily separated by settling or filtration
What is one effect of solutes on solvents?
Solutes lower the freezing point of solvent. Also they higher boiling points
A mixture that has only a little solute dissolved in a certain amount of solvent
One that has a lot of solute in the same amount of solvent
A measure of how much solute can dissolve in a solvent at a given temperature
When you have added so much solute that no more can dissolve
When you are still able to dissolve more solute
How does the pressure and temperature affect the solubility?
The higher the temperature of the liquid the more solute is soluble. The higher than the pressure of the gas the more of the gas that can be dissolved
A substance that taste sour, reacts with metals and carbonates, and turns blue litmus paper red
A substance that taste bitter, feel slippery, and turns red lip this paper blue
A compound that changes color when in contact with an acid or a base example litmus paper
In solutions what ions are formed in acids and bases?
Acids - hydrogen. Bases - hydroxide
What products do acids and bases make when they react question
Water and certain types of salt
Breaks down the complex molecules into smaller onesi
What is the pH of your mouth?
What is the pH of your stomach?
What is the pH of your small intestines?
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