Chapter 5 Flashcards
How are the elements arranged in the modern periodic table?
In the modern periodic table the elements are arranged by increasing atomic number (the number of protons)
Who arranged thee elements into rows in order of “INCREASING MASS” so that the elements with similar properties were in the same row?
Mendelev (Periodic Table)
What is a “period” in the periodic table?
Horizontal rows
In the periodic table, what is a “group”?
The elements in a certain “group” have similar properties. They are the vertical rows 1-18 from left to right
What four pieces of information are given for each element?
(Top) Atomic Number (number of protons)
Element Symbol
Element Name
(Bottom) Atomic Mass (number of protons & neutrons)
What are the three classes of elements?
- Metals
- Nonmetals
- Metalloids
What are “Metals”?
Elements that are good conductors of heat or energy (blue boxes) –solid at room temperature, malleable (bendable), ductile (can be drawn into thin wire)
What are nonmetals?
Elements that are poor conductors of metal or energy. (yellow boxes)
What are “Metalloids”?
Elements with properties that fall between metals and nonmetals. i.e. ability to conduct electricity varies with temperature. (Green Boxes)
What quality of the elements change across the period from left to right?
From Left to Right, the elements become less metallic and more nonmetallic.
What is a “Valence Electron”?
An electron that is in the highest occupied energy level of an atom.
Do elements in a group have similar properties because the have the same number of valence electrons
Yes
What are “alkali metals” (Group 1A)?
Metals that have a single valence electron, but are extremely reactive. Top more reactive —– Bottom less reactive
What are “Alkaline Earth Metals” (Group2A)?
Alkaline Earth Metals have two valence electrons and they are harder than alkali metals; they react differently with water.
What is the “Boron Family”?
(Group3A) these elements have three valence electrons.
What is the “Carbon Family”?
(Group 4A) These elements have four valence electrons
What is the “Nitrogen Family”?
(Group 5A) These elements have five valence electrons.
What is the “Oxygen Family”?
(Group 6A) All the elements in this group have six valence electrons
What are the “Halogens”?
(Group 7A) These elements have seven valence electrons and similar chemical properties; they are highly reactive nonmetals
What are the noble gases?
(Group 8a) All elements except Helium (2) have eight valence electrons, are odorless and colorless gases.
Mendeleev arranged the elements in his periodic table in order of
a. atomic number b. # of electrons c. mass d. # of neutrons
c. Mass
Mendeleev’s decision to leave gaps in his periodic table was supported by the discovery of
a. electrons b. protons c. argon d. gallium
b. potons
In a modern periodic table, elements are arranged in order of
a. atomic # b. # of isotopes c. atomic mass d. # neutrons
a. Atomic Number
