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Periodic Table of Elements
Unit 3 Test Questions
Terms in this set (77)
Where are the metals located on the periodic table?
Where are the nonmetals located on the periodic table?
Where are the metalloids located on the periodic table?
they are located above and below the zig-zag line on the periodic table. (includes: B, Si, Ge, As, Sb, Te)
what are the exceptions to metalloids?
Polonium and Aluminum have physical properties of metals but chemical properties of metalloids. Astatine has physical properties of a nonmetal but chemical properties of metalloids.
How can you identify a metal by its chemical properties?
- most metals are very reactive and form compounds with other elements quite easily. Ex.Sodium and Potassium
- metals lose electrons to form positive ions (cations) when making compounds with nonmetals.
How can you identify a metal by its physical properties?
- shiny luster, malleable and ductile
- metals are good conductors of thermal and electrical energy. Ex. Silver and Copper
How can you identify a nonmetal by its chemical properties?
- Some nonmetals are very reactive and form compounds easily. Ex. Fluorine and Chlorine
- Reactive nonmetals gain electrons to make negative ions when forming compounds with metals. they share electrons when forming compounds with other nonmetals.
How can you identify a nonmetal by its physical properties?
- dull luster and brittle when solid
- nonmetals are poor conductors
How can you identify metalloids?
- elements: some have properties of metals and some properties of nonmetals
How can atoms bond with other elements (types of bonds)?
ionic, covalent, and metallic bonding
What is an Ionic bond?
the electrostatic attraction between the positive cation and a negative anion after one of more electrons are transferred from the metal atom to the nonmetal atom.
How do crystal lattice form?
a crystal lattice is a repeating three dimensional pattern of ions. Ionic compounds are neutral despite the charged atoms composing. strong force of attraction between bonded ions gives ionic compounds certain properties: high melting and boiling points + form brittle solids at room temperature.
When do nonmetals hold more tightly to their electrons?
when they have a nearly full outer energy levels
What is electron affinity and what kind of metals have a higher one?
Electron affinity is how tightly the atom holds onto its electrons. nonmetals have a high electron affinity.
How does hydrogen bonding happen in water?
two hydrogen atoms share their electrons with one oxygen atom. The water molecule is held together by covalent bonds. the molecule has a partial positive end and a partial negative end b/c the oxygen atoms holds the shared electrons more tightly than hydrogen atoms. The negatively charged end of the oxygen atom will be weakly attached to the positively charged end of the hydrogen atom in a different water molecule forming a Hydrogen Bond.
What is a metallic bond and how does it form?
A metallic bond is the force of attraction between positive metal ions and shared electrons.
- In a metal, the atoms are so close together that their electron clouds overlap and the valence electrons are shared among all the atoms.
- electrons are free to move among the positive metallic ions.
- metallic ions are held together by their attraction for the negative electron cloud.
- thus metals are good thermal and electrical conductors and can be reshaped without breaking. (malleable and ductile)
What is absorption and what is emission?
when the electrons in the metal are excited and jump from one electron shell level to the next highest shell level it is called Absorption and they are said to be excited. they cannot remain there so as they return to the original shell, known as the grounded state the energy gained is lost in the form of light known as Emission.
Can you see all the jumps on the spectrum?
There are many possible jumps, but we can only see a few in the visible spectrum.
Why is the word periodic used to describe the table?
The patterns on the table repeat
What is the difference between the way Mendeleev and Moseley organized their periodic table?
Mendeleev - properties (atomic mass)
Moseley - number of protons (atomic number)
What do the rows in the periodic table have alike?
all of the elements in a period have the same number of energy levels or shells in the electron cloud as its row number or period.
What is an electron orbital?
orbitals are areas within atoms where there is a high probability of finding an electron. electrons do not orbit the nucleus in a defined path. instead, they move very quickly around the nucleus in specific areas. these areas are called orbitals.
What do the columns in the periodic table have alike?
the elements in a group have the same number of electrons in their outer shell or energy level
What are valence electrons?
electrons in the outer shell of an atom
How do valence electrons effect an elements reactivity?
electrons with the same number of valence electrons react similarly
How are ions formed?
they are formed by adding or removing electrons
How is hydrogen unique?
- Hydrogen sometimes loses one electron (acts like a metal) and sometimes gains or shares one electron when forming compounds
- diatomic: in nature they forms pairs by sharing electrons
How is helium unique?
- helium has two valence electrons but it is grouped with elements that have eight valence electrons b/c its energy level or shell is filled.
What is an ionic solid?
Ionic solids are solids composed of ionic particles. held together by ionic bonding. bonding results attractive interactions from oppositely charged ions.
What are some characteristics of ionic compounds?
- crystalline solids
- high melting and boiling points
- conduct electricity when melted or dissolved in water
What are some characteristics of covalent compounds?
- gases, liquids, or solids (made of molecules)
- low melting and boiling points
-poor electrical conductors in all phases
What are some typical properties of metals?
- good conductors of heat and electricity
- generally high melting and boiling points
What are some details of metallic bonds?
- the properties of metals suggest that their atoms possess strong bonds
- yet the ease of conduction of heat and electricity suggest that electrons can move freely in all directions in a metal
- the general observations give rise to a picture of "positive ions in a sea of electrons" to describe metallic bonding.
How does metallic bonding happen?
- the atoms in a metallic solid contribute their valence electrons to form a "sea" of electrons that surrounds metallic cations
- delocalized electrons are not held by any specific atom and can move easily throughout the solid
- a metallic bond is the attraction between these electrons and the metallic cation
What is an alloy?
an alloy is a mixture of elements that has metallic properties
What are the two types of alloys?
an Interstital Alloy - is one in which the small holes in a metallic crystal are filled by other smaller atoms.
a Substitutional Alloy - is one in which atoms of the original metal are replaced by other atoms of similar size.
How are ionic bonds made?
formed when atoms joined together by transferring of electrons between metal and nonmetals atom.
How are covalent bonds made?
formed when atom joined together by sharing electron between nonmetal and nonmetal atom
types of covalent bonds: single, double, and triple covalent bonds.
Which kind of covalent bonds are the strongest?
triple covalent bonds
In a solid state, do ionic compounds conduct electricity?
In solid state, ions do not move freely. hence, ionic compound does not conduct electricity in a solid state.
In a aqueous or molten state, do ionic compounds conduct electricity?
In a aqueous or molten state, ions are free to move. hence, the compound can conduct electricity.
Do covalent compounds conduct electricity?
it consists of neutral molecules so it doesn't conduct electricity.
How are the melting and boiling point of ionic compounds decided?
- ionic compounds are held together by strong electrostatic forces
- more heat energy is needed to overcome the strong forces
How are the melting and boiling point of covalent compounds decided?
- covalent compounds are held together by weak intermolecular forces
- less heat energy is needed to over come the weak forces
Which type of covalent bond has equal and unequal sharing of electrons?
nonpolar covalent bond - equal sharing of electrons
polar covalent bond - unequal sharing of electrons
When do polar bonds happen?
polar bonds result when a highly electronegative atom bonds to a less electronegative atom (electronegativity is the ability of an atom to attract electrons in a chemical bond)
How to determine polarity of a covalent bond?
a covalent bond is polar if there is a significant difference between the electronegativities of the two atoms (look at the chart)
What does polarity depend on?
the shape of the molecule
What are the three types of intermolecular forces?
hydrogen bonding, dipole-dipole interactions, dispersion forces
Explain the trend for atomic radius.
the nuclear charge increases as you move from left to right across a period. the increasing charge pulls more strongly on the electrons and causes them to be drawn in. Shielding is not a factor because no new shells are added across a period. so, atomic radius decreases from left to right.
Explain the trend for atomic radius down a group.
The atomic radius increases down a group because a shells is added each time you move down a period. this increases the shielding and causes the electrons to be held less strongly even though there is more nuclear charge.
What happens to the atomic radius of an atom when it becomes an anion or a cation? explain.
An atom becomes an anion by gaining electrons. the added electrons increase the size of the valence shell, causing the anion to be bigger. an atom becomes a cation by losing its valence shells and is therefore smaller.
Explain the trend for electronegativity across a period.
electronegativity increases from left to right across a period because the nuclear charge increases without a change in shielding. this causes an increased attraction for electron. The noble gases are an exception because they have full valence shells
Explain the trend for electronegativity down a group.
electronegativity decreases down a group due to increased shielding. the pull from the nuclear charge is blocked by the added shells
Give one reason that helps explains why helium as the highest first ionization energy on the periodic table.
it only has one shell so there is zero shielding. this causes the atom to be small and to be very tightly held.
Why does shielding not change as you move across a period?
No new shells are added across a period so the shielding stays the same.
Why is called a periodic table?
The table is periodic because the chemical and physical properties of the elements repeat in a predictable way.
What is the octet rule and how does it relate to reactivity? Are there any exceptions?
the octet rule states that atoms react to form full outer shells of electrons. most atoms have eight electrons in their valence shell. the exceptions are hydrogen and helium, their valence shell only.
How is bonding in metals different than bonding in either ionic or covalent compounds?
an ionic bond involves the transfer of an electron from a metal to a nonmetal and a covalent bond involves pairs of electrons being shared between nonmetals. a metal bond is when metal atoms share electrons with other metal atoms.
Why aren't metals brittle?
because the electrons are free to move throughout the material, the atoms can be moved around. this makes the material malleable.
Name three things that metals are uniquely good for given their properties.
they make good mirrors because of their shiny luster. they are useful in jewelry because they are malleable. they are good for making houses because they are ductile and conductive
Why are salts brittle?
because salts are ionic compounds. the atoms in a salt have to be in predetermined places (+-+-). this makes it valuable to break apart.
what group on the periodic table have seven valence electrons?
What type of bond happens between nonmetals with similar electronegativity?
What type of bond happens between elements with large differences in their electronegativity values?
ionic or polar covalent
True/False: Many elements were predicated to exist before they were discovered.
True/False: A shiny, conductive, and brittle element would be a metal.
True/False: Two metals can form a covalent bond.
True/False: Every carbon atom has the same number of neutrons.
True/False: NaCl would be an example of a diatomic molecule.
True/False: The Alkali metals are more reactive than Alkaline Earth metals.
True/False: Every element in the carbon group is a nonmetal.
True/False: Hydrogen can form a double covalent bond.
How does the polarity of alcohol and water molecules affect the surface tension of each liquid?
The water has more attraction and a stronger pull to each other molecule so it can hold more drops compared to the alcohol.
Use the concept of polarity to explain why alcohol evaporates faster than water.
The alcohol doesn't hold on a strong as water so it evaporates.
Knowing what you do about the polarity of water and alcohol, explain why alcohol boils at a lower temperature than water.
water has a higher polarity which means it has more strength to hold on to other molecules compared to alcohol. the heat needs to split the molecules and it easier to do so at a lower degree because they aren't holding on as tight.
If water absorbs into a paper towel but does not absorb into wax paper, what does that say about the polarity of paper and the polarity of wax paper?
the paper has molecules that attract water and so it absorbs but wax paper doesn't have molecules that attract water so it doesn't absorb. wax paper is a non polar substance. water is attracted to molecules in paper. paper is therefore polar.
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