Unit 2 Flashcards
(105 cards)
What are Elements? Explain them.
Elements are pure substances from which all other things are built.
- They cannot be broken down into simpler substances.
- They can join with other elements to form compounds.
What are Chemical Symbols?
Chemical Symbols represent the names of the elements. They consist of one or two letters.
Ex: C -> Carbon
Ex: Al -> Aluminum
Explain the Periodic Table.
- The periodic table organizes elements. Elements are arranged according to properties
- Groups (or families) contain elements with similar properties in vertical columns.
- Periods are horizontal rows of elements, counted from top to bottom.
How many periods and groups (families) are there?
There are 7 Periods and 18 groups
Explain group numbers.
Group numbers are written at the top of each vertical column.
- The letter A is for representative elements (1A-8A)
- The letter B is for transition elements (3B-12B)
An alternative system uses numbers 1-18 for all the groups.
Where are Alkali Metals located?
Group 1
- Alkali Metals are very reactive
Where are Alkaline Earth Metals located?
Group 2
- Not as reactive as group 1 metals
Where are Transition Metals located?
Group 3-12
Where are Halogens located?
Group 17
- They are highly reactive and form compounds with most elements
Where are Noble Gases located?
Group 18
Explain Metals
All metals Except hydrogen are located on the left of the periodic table.
- They are shiny and ductile, and conduct heat and electricity.
- They are solid, except for mercury (Hg).
Explain Nonmetals
Located on the right side of the periodic table including hydrogen.
- They are dull, brittle, and poor conductors but often good insulators.
- They have low densities and melting points.
Explain Metalloids
Located along the heavy zigzag line on the periodic table.
- Exhibit properties of metals and nonmetals
- Are better conductors than nonmetals but not as good as metals.
What are the 4 elements that make up the majority of our body mass?
Oxygen, Carbon, Hydrogen, Nitrogen
- Makes up 96% of our body mass
What are Macrominerals?
Elements that are essential to our health.
What is an Atom?
An atom is the smallest particle of an element that retains the characteristics of that element.
What is the Dalton Atomic Theory?
Atoms…
- are tiny particles of matter of an element
- are similar to each other and different from those of other elements
- of two or more different elements combine to form compounds
- are rearranged to form new combinations in a chemical reaction
!! Atoms are never created or destroyed during a chemical reaction!!
What makes up an Atom? Explain
Protons: have a positive charge
Electrons: have a negative charge
Neutrons: have no charge
- Like charges repel and unlike charges attract
Where is the Nucleus located? What does it contain?
A nucleus is located in the center of the atom, which contains protons and neutrons.
Explain the Mass of the Atom.
In an atom, the protons and neutrons that makeup almost all the mass are packed into the tiny volume of the nucleus. The electrons surround the nucleus and account for the large volume of the atom.
What is the Atomic Mass Unit (amu)?
Because the mass of subatomic particles is so small, chemists use a very small unit of mass called the atomic mass unit (amu)
- 1 amu = 1 Dalton
- !!Electrons have such a small mass that they are not usually included in the mass of an atom!!
What is the symbol, charge, mass, and location of a Proton?
Symbol: p+
Charge: +1
Mass (amu): 1.007
Location in Atom: Nucleus
What is the symbol, charge, mass, and location of a Neutron?
Symbol: n
Charge: 0
Mass (amu): 1.008
Location in Atom: Nucleus
What is the symbol, charge, mass, and location of a Electron?
Symbol: e-
Charge: -1
Mass (amu): 0.00055
Location in Atom: Outside the Nucleus