Chapter 4 Test Review Flashcards
Explain the method that John Newland used to organize elements.
He arranged the known elements in order of increasing atomic mass and used the law of octaves.
What method did Dmitri Mendeleev use to arrange his periodic table?
He created the first periodic table by atomic mass and properties using Newland’s observations.
Why did Mendeleev have gaps in his table? How did he use these gaps?
Mendeleev left gaps in the table for elements that have not yet been discovered and was able to predict these unknown elements properties.
What was Henry Moseley’s contribution to the periodic table?
Provided the base to organize the elements on the table
Explain the importance of valence electrons.
Valence electrons determine the atom’s chemical properties and are the electrons in the outermost shell of the atom.
Why do elements with similar properties appear at regular intervals in the periodic table?
It shows periodic law which means elements are sorted by atomic number which lets elements with similar properties appear at regular intervals.
How is the electron configuration similar for each element in a group?
The ending sublevel is always the same as the group it is.
How is the electron configuration similar for each element in a period?
The same number of energy levels are filled.
The ___ have a single electron in the highest occupied energy level.
Alkali metals
The ____ are in the s- and p-blocks of the periodic table.
main-group elements
All the _____ have two valence electrons and get to a stable e- configuration by losing two electrons.
Alkaline earth metals
Unlike the main group elements, each group of the _____ does not have the identical outer electron configuration.
transition metals
The ____, the most reactive group of nonmetals, achieve stable electron configurations by gaining one electron.
halogens
The ___ have a full set of electrons in their outermost energy level.
noble gases
The ___ are highly reactive and readily form salts with metals.
halogens
The ____ are very stable and have low reactivity
noble gases
In general, the _____ are metals that are less reactive than the alkali metals and the alkali earth metals.
transition metals
The____ are metals that lose one electron when they react with water to form alkaline solutions.
alkali metals
Most elements are ____
metals
With its one valence electron, _____ reacts with many other elements.
hydrogen
Which groups compose the main-group elements?
1,2, 13-18
Why are the main-group elements called the representative elements?
They have a wide range of properties
Why are Group 2 elements less reactive than Group 1 elements?
Group 2 have 2 valence electrons and would have to lose both to become stable.
Using electron configurations, explain why the halogens readily react with the alkali metals to form salts.
Halogens need to gain one electron and alkali metals will lose the electron.
Why is an iron alloy, such as steel, preferred over pure iron?
They tend to be harder, stronger, and more resistant to corrosion
In the transition elements, electrons are usually added to the __ orbital, which is why these elements are also known as the _________
d, d-block elements
The ___ include all members of Groups 1 through 12, as well as some of the elements of Groups ___ through _____.
metals, 13, 16
The ___ include all of the elements in Group 17 and 18 as well as some members of Groups __ through ____.
non-metals, 14,16
In the _____, electrons are being added to the 4f orbitals.
lanthanides
In the _____, electrons are being added to the 5f orbitals. The ____ are unique in all that are unstable and radioactive.
actinides
The amount of energy needed to remove an electron from a specific atom is called the ___ energy of an atom.
ionization
____ is the energy change that occurs when a neutral atom gains an electron
Electron affinity
The ____ is half the distance from center to center of two atoms bonded together.
bond radius
_____ is a numerical value that reflects how much an atom in a molecule attracts electrons.
electronegativity
As the nuclear charge increases across a period, the effective nuclear charge ______________ pulling the electrons closer to the nucleus and ____________ the size of the atom.
increases, decreases
Explain why the exact size of an atom is difficult to determine.
An atom’s size depends on electrons that move, so the electron cloud has a “fuzzy” boundary.
What is electron shielding?
Inner electrons shield outer electrons from the nucleus
Explain why ionization energies tend to decrease down a group.
the outermost electron is farther from the nucleus, meaning it is held less tightly and requires less energy to remove
Explain the large decrease in atomic radii as you move across a period from group 1 to group 14:
As the outermost electrons are pulled closer to the nucleus, they also get closer to one another and repulsion gets stronger.
Explain the large increase in electronegativity as you move across a period:
each atom has one more proton and one more electron in the same principal energy level than the one before it. Therefore because electron shielding does not change, the nuclear charge increases across a period, attracting the electrons more strongly.
Describe the periodic trend of ionization energy.
Decreases down a group, increases across a period from left to right
Describe the periodic trend of atomic radius.
Increases down a group, decreases moving across a period from left to right
Describe the periodic trend of ionic size.
Increases down a group, decreases across a period from left to right
Describe the periodic trend in electron affinity.
Decreases down a group, increases across a period from left to right
Describe the periodic trend of electronegativity.
Decreases down a group, increases across a period from left to right
What is the octet rule?
the tendency of atoms to prefer to have eight electrons in the valence shell
Atomic radii cannot be measured directly because the electron cloud surrounding the nucleus does not have a clearly defined____
mass
The general trend in the radius of an atom moving down a group is partially accounted for by the ____
shielding of the outer electrons by the inner electrons
What is the periodic table?
A table that organizes elements by their properties
Elements on our periodic table are in order of increasing
both atomic number and number of protons
Elements with similar electron configurations ____
have similar reactivities
Metalloids are ____
semi-conductors
Electron Affinity is ____
the amount of energy required to add an electron to an atom
Electronegativity is ____
the measure of the tendency an atom to attract electrons
