Chapter 7 Test Study Guide Flashcards
What is an atom and an element?
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What is a compound?
Two or more elements chemically combined.
What was Dalton’s model of the atom?
- all matter is made up of atoms
- atoms of each element are the same.
- different elements have different masses.
- atoms of different elements can join to form compounds.
early 1800s; based on experiments with gases; hydrogen and oxygen-water; atoms like a solid sphere.
What is an electron, who identified, and where in an atom is it found?
an electron is a subatomic particle that has negative charge and is located outside of the atom’s nucleus. Joseph Thompson discovered in in the late 1800s.
What is a proton and where in the atom can it be found?
A proton is a subatomic particle located in the nucleus of the atom and has a positive charge.
What is the nucleus of an atom, who identified it, and what does it contain?
Discovered by Rutherford, the nucleus contains protons and neutrons, and the nucleus is the central region of the atom.
What are energy levels and who first described them?
Energy levels move electrons around the atom. Niels Bohr was the first to describe them.
Name and describe the current model of an atom.
The “Electron Cloud Modes” 1. electrons don’t orbit around the nucleus. 2. electrons travel in an energy level but in ever-changing paths.
What is a neutron and where is it found in the atom?
A subatomic particle with no electric charge located in the nucleus.
What is the atomic number of an atom?
Is the number of protons and electrons an atom has. It is used to identify elements.
How is the atomic number related to the number of electrons in an atom?
The atomic number tells you how many protons are in an atom. Protons are positive and an atom needs to be neutral; so if there are 5 protons there has to be 5 neutrons.
What is the atomic mass of an atom?
number of protons and neutrons an atom has. (used to identify isotopes)
How many protons, neutrons and electrons are in this atom?
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What is an isotope
an isotope is atoms of the same element that have different numbers of neutrons and therefore different atomic masses.
What is different between H-3 and H-2
They have a different atomic mass. It is an isotope.
What is a diatomic compound?
DC-gases that occur in nature always as a pair (never alone) ex: oxygen o2, hydrogen H2 and iodine Ix (etc)
What is a “BrINCIHOF” gas?
The 7 gases that are diatomic compounds. Bromine, Iodine, Nitrogen, Chlorine, Hydrogen, Oxygen, and Florine.
What is the relative abundance of solid, liquid and gaseous elements?
Most are solids, followed by gases, followed by liquids.
What is a chemical symbol?
Chemical symbols represent an element. 1 or 2 letters (First letter is capitalized)
What are some examples of elements and their chemical symbols?
Hydrogen: H
Helium: He
Nitrogen: N
Uranium: Ur
How do the properties of a compound relate to the properties of the elements used to create it?
- elements combined=to make a compound.
- most are solids at room temperature.
- metal can conduct electricity.
- 2 liquids at room temperature.
What does it mean that compound have definite chemical composition?
the ratio of elements is always the same.
What is molecular compound?
- 2 or more elements help together sharing electrons.
- sharing electrons is a covalent bond.
- most liquids and gases are molecular compounds.
What is a covalent bond?
shared electrons. O–> O- =O=O ex: Hydrogen H2
