chemistry chapter 7
Most metals have a range of how many valence electrons?
1-3
Write the chemical formula for the compound that is created when the following elements react: calcium and oxygen
CaO
Metal atoms lose the number of electrons necessary to attain the electron configuration of what kind of element?
a noble gas
What can the valence electrons of atoms in a pure metal be modeled as?
a sea of electrons
What is an octet?
a set of eight
Which of the following compounds are most likely not ionic? select one or more: a. NH3 b. H2O c. CO2 d. Na2O e. SO2 f. CaS
a, b, c, e
Which pairs of elements are likely to form ionic compounds? select one or more: a. I, Na b. Cl, Br c. K, He d. Li, Cl
a, d
Identify the charge and magnitude of the ion formed when: a. a potassium loses one electron b. a zinc atom loses two electrons c. a flourine atom gains one electron
a. +1 b. +2 c. -1
How many valence electrons are in each atom? a. potassium b. carbon c. magnesium d. oxygen
a. 1 b. 4 c. 2 d. 6
Name each ion and identify each as an anion or cation: a. Ba2+ b. As3- c. Ca2+ d. Cu+ e. Br- f. Na+ g. Cu2+ h. H-
a. Barium, cation b. arsenide, anion c. calcium, cation d. copper(1), cation e. bromide, anion f. sodium, cation g. copper(2), cation h. hydride, anion
What is meant by the following terms? a. ductile b. malleable
a. able to be drawn into wires b. able to be hammered or pressed into shapes
State the number of electrons either lost or gained in forming each ion. a. Cu+ b. Ba2+ c. H- d. Ca2+ e. As3- f. Na+ g. Cu2+ h. Br-
a. lose 1 b. lose 2 c. gain 1 d. lose 2 e. gain 3 f. lose 1 g. lose 2 h. gain 1
In terms of electrons why are metals ductile and malleable?
because when metal is subject to pressure, because of its sea of drifting valance electrons, the cations easily slide past one another
What does it mean that metals are malleable?
they can be hammered and pressed into shapes
How do chemists model the valence electrons of metal atoms?
they can be modeled as a sea of electrons
If, when forming an alloy, the atoms of the components are the same size, what happens?
they can replace each other in the crystal
How do the charges of cations of the transitional metals relate to each other?
they don't, they vary
Are metal atoms tightly packed or loosly packed?
tightly packed
How does the name of an ion change from its original name?
typically ends in ide
What are the electrons in the highest occupied energy level of an element's atoms called?
valence electrons
What are the only electrons involved in chemical bonds called?
valence electrons
Which electrons are involved in electron dot structures?
valence electrons
When is an anion produced?
when an atom gains one or more valence electrons
When is a positively charged ion, or cation, is produced?
when an atom loses one or more valence electrons
How do anions form?
when an atom or group of atoms gain an electron
How are cations formed?
when an atom or group of atoms loses an electron
When is an ion formed?
when an atom or group of atoms loses or gains electrons
are metals crystaline?
yes
What does it mean that metals are ductile?
they can be drawn into wires
Write the electron configuration of Mg2+
1s2, 2s2, 2p6
all halogen atoms have ___ valence electrons and need to gain ____ electron/s to achieve the configuration of a noble gas.
7, 1
Write the formula of the compound that forms when the following ions react: Al3+ and S2-
Al2S3
Write the formula of the compound that forms when the following ions react: Ba2+ and Br-
BaBr2
Why does an anion have a negative charge?
Because when you add an electron he overall charge of the atom becomes negative
Write the chemical formula for the compound that is created when the following elements react: aluminum and nitrogen
HELP!!!!!!
What is a hexogonal close packed arrangement?
It is a structure that can take place with metal atoms where every atom has 12 neighbors, but since the atom is in a hexagonal shape that patterns are different that in a face centered cubic arrangement
Write the chemical formula for the compound that is created when the following elements react: potassium and sulfur
K2S
Write the formula of the compound that forms when the following ions react: K+ and N3-
K3N
Write the chemical formula for the compound that is created when the following elements react: sodium and oxygen
Na2O
Are there any exceptions to the octet rule?
Some of the transitional metals
In terms of electrons, why does a cation have positive charge?
a cation has lost one or more electrons
Define ionic compound
a compound composed of anions and cations
How many electrons whill each element gain or lose in forming an ion? Select the word "lose" or "gain" and type the number. a. calcium b. flourine c. aluminum d. oxygen
a. lose 2 b. flourine 1 c. lose 3 d. gain 2
a. Atoms of which elements (metals or nonmetals) tend to lose electrons? b. Atoms of which elements (metals or nonmetals) tend to gain electrons?
a. metals b. nonmetals
Write the name and symbol of ion formed when: a. sulfur gains 2 electrons b. aluminum loses 3 electrons c. nitrogen gains 3 electrons d. calcium loses 2 electrons
a. sulfide anion, S2- b. aluminum ion, Al3+ c. nitride anion, N3- d. calcium ion, Ca2+
Which of the following pairs of atoms would you expect to combine chemically to form an ionic compound? a. Al and O b. H and N c. I and K d. F and Cl e. Li and S f. O and S
a. yes b. no c. yes d. no e. yes f. no
What is the relationship between an element's electron dot structure and the location of the element on the periodic table?
all elements within a given group have the same number of electron dots on their structures
What are most of the metals we encounter on a daily basis called/
alloys
What is an anion?
an atom or group of atoms with a negative charge
What does it mean pseudo noble-gas configuration?
an ion that has 18 electrons in the highest occupied energy level instead of eight
How do ionic compounds exist?
as collections of positively and negatively charged ions arranged in repeating patterns
Although they are composed of ions, ionic compounds are: a. positively charged b. electrically neutral c. negatively charged
b
1. Which of the following will conduct electricity? a. NaCl solid b. Dissolved NaCl in water c. NaCl powder 2. Why does the answer to the question above conduct electricity?
b, because when dissolved the ions are free to move about the solution
Why can alloys be more useful than pure metals? select one or more: a. alloys will never rust b. properties of alloys might be superior than the individual metals in the alloy c. alloys might not have undesirable properties that the individual elements have d. alloys can be more durable than the metals from which they are created
b, c, d
Check all that are properties of ionic compounds. select one or more: a. often gases at room temperature b. have high melting points c. usually solid at room temperature d. conduct electricity as solids e. conduct electricity when melted or dissolved in water
b, c, e
Why are electrons good conductors of electric current?
because electrons can flow freely throughout the metal and as electrons enter one end of a bar an equal number of electrons leaves the other end
Why cant ionic crystal be malleable and ductile?
because the blow tends to punch the already tightly wound ions closer together. they repel each other and the crystal shatters
Why is it possible to bend metals but not ionic crystals?
because the valence electrons in metals are free flowing, but the valence electrons in ionic crystals have a strong bond with their atoms
Why are alloys important?
because their properties are often superior to those of their component elements
Why are the valence electrons of atoms in a pure metal modeled as a sea of electrons?
because they are mobile and can drift freely from one part of the metal to another
Why do all the elements within each group of the periodic table react in a similar way?
because they have the same number of valence electrons.
Why do ionic compounds conduct electricity when dissolved in water?
because when dissolved in water the ions are free to move about the solution
How can you determine the number of valence electrons in a representative element?
by looking at the group number.
Which ionic substances are brittle. Why? a. positive ions attract other positive ions b. unless a metalloid is present, compounds will be brittle c. each ion is strongly attracted to its neighbors in the compound d. metals do not usually form any sort of bond with nonmetals
c
What are most ionic compounds at room temperature?
crystalline solids
Which electron does sodium lose to form the Na+ ion? a. 1s2 b. 2s2 c. 3s2 d. 3s1
d
What are electron dot structures?
diagrams that show valence electrons in the atoms of an element as dots
Are all alloys formed from their component atoms in the same way or different ways?
different ways
Explain why metals are good conductors of electric current.
electrons can flow freely through the metal
Anions and cations have opposite charges and attract one another by means of _______
electrostatic forces
Atoms of nonmetals tend to ___ electrons or to ___ electrons with another nonmetal atom or atoms to achieve a complete ___.
gain, share, octet
What are the ions produced when atoms of chlorine and other halogens gain electrons called?
halide ions
What are the characteristics of ionic compounds?
have high melting points, can conduct electric current when melted or dissolved in water, usually solid at room temperature
What do metallic bonds do?
hold metals together
What does the octet rule state?
in forming compounds, atoms tend to achieve the electron configuration of a noble gas.
The component ions in ionic compounds are arranged usually how?
in repeating three dimensional patterns
What are the electrostatic forces that hold ions together in ionic compounds called?
ionic bonds
What is a face centered cubic arrangement?
it is a structure that can take place with metal atoms where every atom has 12 neighbors
What is a body centered cubic structure?
it is a structure that can take place with metal atoms where every atom has eight neighbors
For metals, what changes about the name of the cation?
it stays the same as the regular element's name
Atoms of metals tend to ___ their electrons, leaving a complete octet in the ___ energy level.
lose, next lowest
Atoms of nonmetalic elements attain noble gas electron configurations more easily by ___ electrons than by ___ them because these atoms have relatively full valence shells.
losing, gaining
Most commonly, cations are produced most commonly by what class of element?
metal
What are among the simplest forms of crystaline solids?
metals that contain just one kind of atom
What are alloys?
mixtures of two or more elements, at least one of each is a metal
The octet rule applies to atoms in ____ compounds.
most
Are ionic charges shown when you write the formula unit of the compound?
no
Do all ions formed by transitional metals have noble gas configurations?
no
Do ionic compounds exist as single discrete units?
no
What are the most important alloys of today?
steels
What is the alloy called when the atoms of the components can replace each other in the crystal?
substitutional alloy
What does a formula unit refer to?
the chemical formula of an ionic compound
What do valence electrons have a large part in determining about their respective elements?
the chemical properties of the element
What are metallic bonds?
the forces of attraction between the free-floating valence electrons and the positively charged metal ions
What number on the periodic table do you have to look at to find the number of valence electrons in an element?
the group number
Define formula unit
the lowest whole-number ratio of ions in an ionic compound
What does a chemical formula show?
the number of atoms in each element in the smallest representative unit of a substance
What is the coordination number of an ion?
the number of ions of opposite charge that surround the ion in a crystal
What rule explains why atoms form certain kinds of ions and molecules?
the octet rule
What are major differences between a metal element and its cation?
there are major chemical differences
