Science Chapter 5
What does each element family have in common?
The elements in a family have the same number of valence electrons.
How are elements arranged in the modern periodic table?
The modern periodic table organizes elements by atomic number. When the elements are arranged in this way, elements that have similar properties appear at regular intervals.
Groups 3-12...
Transition metals. Varied.
How many groups does the periodic table have?
18.
Group 1...
Alkali metals. And 1 valence electron
Group 2...
Alkali-earth metals, And 2 valence electrons.
What do elements become across each period?
Elements become less metallic across each period.
What else can elements be grouped into?
Elements can be grouped into families. The elements in each family have the same number of valence electrons. As a result, they have similar chemical properties.
What year did Mendeleev publish the first periodic table?
In 1869, Mendeleev published the first periodic table of the elements.
Did all of the elements fit the pattern?
No.
How many compounds contain carbon?
There are millions of carbon-containing compounds.
period
a horizontal row of elements in the periodic table
group
a vertical column of elements in the periodic table; element in a group share chemical properties
nonmetal
an element that conducts heat and electricity poorly
What are alkali metals mostly stored in to keep them nonreactive?
oil
halogens
one of the elements of Group 17 of the periodic table
If the element ununoctium is ever synthizized, it will be located directly under radon, xenon and krypton on the periodic table. What would ununoctium's atomic number be? Predict ununoctium's properties.
118. It would fall in with the noble gases so it would be nonreactive and have a full outer shell.
At what date was germanium discovered?
1886.
Carbon, whose atomic number is 6, has four valence electrons. Sulfur's atomic number is 16, and sulfur is located two columns to the right of carbon and one row down on the periodic table. How many valence electrons does sulfur have?
6
How many periods does the periodic table have?
7.
What does the symbol Li+ represent?
A lithium ion.
Tell about alkali-earth metals...
Alkaline-earth metals form compounds that are found in limestone and in the human body. Alkaline- earth metals are in group 2. Alkaline-earth metals are less reactive than alkali metals, but still react to form positive ions. Alkaline-earth metals are harder, denser, stronger, and have higher melting points than alkali metals.
What are the three main categories of elements?
All elements are either metals, non metals or semiconductors.
Why did they change the arrangement of the periodic table from atomic mass to atomic number?
Arranging the table by atomic number rather than by atomic mass fixed the discrepancies in Mendeleev's table.
What are semiconductors?
As their name suggests, semiconductors are able to conduct heat and electricity under certain conditions.
Why are the elements in Group 1 the most reactive?
Because the single valence electron is easily removed. Also its made up of alkali metals and they are extremely reactive.
What do elements in a group have?
Elements in a group have similar properties.
What are the families of metals?
Families of metals include the alkali metals, the alkaline-earth metals, and the transition metals.
What are some of the families of nonmetals?
Families of nonmetals include the noble gases and the halogens.
What do Group 1 elements form?
Group 1 elements form positive ions, because the single valence electron is easily removed.
What do Group 17 elements form?
Group 17 elements form negative ions, because the addition of one valence electron fills the outer energy level.
Group 17...
Halogens. And 7 valence electrons.
What class in hydrogen apart of?
Hydrogen is in a class by itself and is the most abundant element in the universe.
What happens to an to an atom that gains or loses electrons?
If an atom gains or loses electrons, it no longer has an equal number of electrons and protons. Because the charges do not cancel completely the atom has a net electric charge.
ion formation
If an atom gains or loses electrons, it no longer has an equal number of electrons and protons. Because the charges do not cancel completely, the atom—now called an ion—has a net electric charge.
How did Mendeleev arrange the elements in his periodic table?
In his periodic table, Mendeleev arranged elements in rows by increasing atomic mass.
How did Mendeleev predict new elements on the periodic table?
Mendeleev left spaces in his table to make the pattern fit. He used the spaces to successfully predict the existence and properties of elements not yet discovered.
Which category contains the most elements, and which category contains the fewest elements?
Metals contain the most and semiconductors contain the least amount.
What group of elements is the least reactive?
Noble Gases.
Group 18...
Noble gases. 8 valence electrons except for helium which only has 2.
What happens as you move from left to right of a period on the periodic table?
Properties such as re-activity and conductivity change, and elements become less metallic.
What group of elements has some properties of metals and some properties of nonmetals? How does the periodic table reflect this fact?
Semiconductors. The periodic table shows this because they put them between the metals and the nonmetals.
How many other nonmetals are on the right side of the periodic table?
Six. Carbon, nitrogen, oxygen, phosphorus, sulfur, and selenium
Tell about alkali-metals...
The alkali metals are very reactive. Alkali metals are in Group 1, on the left edge of the periodic table. They are reactive because they have one valence electron that is easily removed. They are soft and shiny,and many have similar melting points, boiling points, and densities.
What does the prefix eka- mean, in terms of the layout of the periodic table?
The element 'one down'.
What information about an element is most crucial for locating that element in the periodic table?
The elements atomic number.
Tell about halogens...
The halogens combine easily with metals to form salts. The halogens are in Group 17. With the edition of a single electron, halogens become stable. They combine easily with metals (especially with alkali metals) to form salts.
Tell about noble gases...
The noble gases are relatively inert (nonreactive). The noble gases are in Group 18. They exist as single atoms instead of molecules. They are inert, or nonreactive, because their s and p orbitals are filled, In general, they do not form ions or compounds.
Why do elements within a group of the periodic table have similar chemical properties?
The periodic trends in the periodic table are the result of electron arrangement. Valence electrons account for similar properties. An element's location in the periodic table is related to electron arrangement.
Tell about transition metals...
Transition metals are in the middle of the periodic table. With the exception of mercury, transition metals are harder, more dense, and have higher melting points than alkali metals and alkaline-earth metals. They are also less reactive, but they can form positive ions.
ion
an atom, radical, or molecule that has gained or lost one or more electrons and has a negative or positive charge
semiconductor
an element of compound that conducts electric current better than an insulator does but not as well as a conductor does
metal
an element that is shiney and that conducts heat and electricity well
noble gas
one of the elements of Group 18 of the periodic table
alkaline-earth metal
one of the elements of Group 2 of periodic table
alkali metal
one of the elements on Group 1 of the periodic table and reacts violently with water
transition metal
one of the metals that can use the inner shell before using the outer shell to bond
What does the word diffused mean?
spread apart.
periodic law
the law that states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements.
