Structure Of Molecules Flashcards
What force keeps atoms together in substances?
Chemical bond
Which elements exist as atoms?
All elements except noble gases
What are molecules of the same element made of?
The same kind of atoms (e.g., O₂, H₂)
What is the process called when atoms combine with one another?
Chemical bonding
Why do atoms form chemical bonds?
To decrease their energy and attain stability
Atoms tend to increase their energy by combining with other atoms. (True/False)
False
All atoms can form chemical bonds to become stable. (True/False)
True
What does the valence concept state?
B) Atoms combine by losing, gaining, or sharing electrons
In the Octet theory of valence, how many electrons do atoms try to have in their outermost shell?
Eight
Which noble gas has only two electrons in its outermost shell?
Helium (He)
Which rule explains the tendency of atoms to have eight electrons in their outermost shell for stability?
Octet Rule
Atoms of which group in the periodic table are called noble gases?
Group VIII
What is the other name for noble gases?
Inert gases
Helium, Neon, and Argon have how many electrons in their outermost shell?
Eight
Atoms of noble gases are very stable because they have a full outer shell. (True/False)
True
How many electrons does Helium have in its outermost shell?
Two
How many electrons does the outermost shell of noble gases have?
Eight (except Helium, which has two)
Why do atoms tend to form chemical bonds?
To complete eight electrons in their outermost shell to attain the noble gas configuration
What is the concept where atoms combine by sharing electrons to complete their outermost shell?
The Octet Rule
Which orbitals overlap to form a sigma bond?
Endwise overlapping
Which orbitals overlap to form a pi bond?
Sidewise overlapping
What are the electrons involved in bond formation called?
Bonding electrons
What is the outermost shell of an atom where loss, gain, or sharing of electrons takes place called?
Valence shell
Which electrons do not take part in bonding?
Non-bonding electrons
In a chemical reaction, what happens to the bonds between elements?
The bonds are rearranged
How many types of bonds are there?
Four
Which bond is formed due to the complete transfer of electrons between atoms?
Ionic bond
What is the force that holds atoms together in an ionic bond called?
Electrostatic force of attraction
Which type of bond is formed between a metal and a non-metal?
Ionic bond
What does a metal atom do to form a cation?
It loses electrons
What does a non-metal atom do to form an anion?
It gains electrons
What is the formation of Sodium Chloride (NaCl) an example of?
Ionic bond formation
Sodium (Na) has one electron in its outermost shell. What does it do to achieve stability?
It loses one electron to form a cation (Na⁺)
Chlorine (Cl) has seven electrons in its outermost shell. What does it do to achieve stability?
It gains one electron to form an anion (Cl⁻)
Which element forms a cation in the formation of Sodium Chloride?
Sodium (Na)
Which element forms an anion in the formation of Sodium Chloride?
Chlorine (Cl)
Opposite charges between ions attract each other. (True/False)
True
What is the result of the ionic bond formation between Na⁺ and Cl⁻?
Sodium Chloride (NaCl)
Which atoms are involved in the formation of Sodium Chloride (NaCl)?
Sodium (Na) and Chlorine (Cl)
In ionic bonding, what is formed when atoms lose or gain electrons?
Ions
Which force keeps the ions together in an ionic bond?
Electrostatic force of attraction
How does Sodium achieve the electronic configuration of Neon?
By losing one electron to form a cation (Na⁺)
How does Chlorine achieve the electronic configuration of Argon?
By gaining one electron to form an anion (Cl⁻)
What is the electron configuration of a neutral Sodium (Na) atom?
11 protons and 11 electrons
What happens to Sodium (Na) when it loses an electron?
It becomes a Sodium ion (Na⁺) with 10 electrons
How many electrons does Chlorine (Cl) need to complete its outer shell?
One electron
What happens to Chlorine (Cl) when it gains an electron?
It becomes a Chloride ion (Cl⁻) with 18 electrons
What type of bond is formed between Sodium (Na) and Chlorine (Cl)?
Ionic bond
What is formed when Sodium (Na) loses one electron and Chlorine (Cl) gains one electron?
Sodium Chloride (NaCl)
How many electrons does Sodium (Na) have in its outer shell after it becomes a Sodium ion?
Eight electrons
How does Chlorine (Cl) achieve the electronic configuration of Argon?
By gaining one electron to form a chloride ion (Cl⁻)
In the formation of Calcium Chloride (CaCl₂), how many electrons does Calcium (Ca) lose?
Two electrons
How many electrons does Calcium (Ca) need to lose to achieve the electronic configuration of Neon?
Two electrons
What is the result when Calcium (Ca) loses two electrons and Chlorine (Cl) gains one electron?
Calcium Chloride (CaCl₂)
How many chloride ions are needed to combine with one Calcium ion to form Calcium Chloride (CaCl₂)?
Two chloride ions
Magnesium (Mg) loses two electrons to form which ion?
Magnesium ion (Mg²⁺)
What is the electronic configuration of a Magnesium (Mg) ion?
2, 8
Which elements form ionic bonds with Chlorine (Cl)?
Metals
What type of bond is formed between a metal and a non-metal?
Ionic bond
Magnesium chloride (MgCl₂) is formed from which elements?
Magnesium (Mg) and Chlorine (Cl)
How many electrons does Magnesium (Mg) lose to form a magnesium ion (Mg²⁺)?
Two electrons
What is the formula for Magnesium Chloride?
MgCl₂
How many electrons does Lithium (Li) have in its outermost shell?
One electron
How many electrons does Oxygen (O) need to complete its outer shell?
Two electrons
What is the result when Lithium (Li) and Oxygen (O) combine to form a compound?
Lithium Oxide (Li₂O)
True or False: Sodium (Na) becomes stable by losing one electron. (True/False)
True
True or False: Chlorine (Cl) becomes stable by losing one electron. (True/False)
False
True or False: Calcium (Ca) forms a divalent ion. (True/False)
True
Fill in the blank: Magnesium (Mg) and Chlorine (Cl) form ________ bond to produce Magnesium Chloride (MgCl₂).
Ionic
Fill in the blank: The formula for the Ionic compound formed between Calcium (Ca) and Chlorine (Cl) is ________.
CaCl₂
Which two elements are involved in the formation of Sodium Chloride (NaCl)?
Sodium (Na) and Chlorine (Cl)
How many chloride ions (Cl⁻) are needed to balance the charge of one calcium ion (Ca²⁺)?
Two chloride ions
What is the bond type between Magnesium (Mg) and Oxygen (O)?
Ionic bond
How many electrons does Fluorine (F) need to gain to complete its outer shell?
One electron
Draw the ionic bond formation for Magnesium Oxide (MgO).
Magnesium loses two electrons, Oxygen gains two electrons, forming Mg²⁺ and O²⁻.
Which elements form a covalent bond in water (H₂O)?
Hydrogen and Oxygen
What is a covalent bond?
A covalent bond is formed when two atoms share electrons to attain stable electronic configurations.
Which types of elements generally form covalent bonds?
Non-metals
True or False: Covalent bonds are typically formed between metals. (True/False)
False
What is the formula of the molecule formed by two hydrogen atoms?
H₂
How is the shared pair of electrons in a covalent bond represented?
By a dash (—) between the two bonded atoms.
What is the name of the bond formed when two hydrogen atoms share electrons?
Covalent bond
Fill in the blank: A covalent bond is formed when two atoms are joined by ________.
sharing of electrons
In the molecule H₂, how many electrons are shared between the two hydrogen atoms?
Two electrons
What is the bond type between two hydrogen atoms in a molecule of hydrogen (H₂)?
Covalent bond
Which molecule is formed when two hydrogen atoms share electrons?
Hydrogen molecule (H₂)
What type of bond is formed in the molecule HCl?
Single covalent bond
What is represented by a single line (—) in a covalent bond?
A single covalent bond where two atoms share one pair of electrons.
How many types of covalent bonds are there?
Three types
Which of the following elements commonly form covalent bonds? (Hydrogen, Sodium, Oxygen, Calcium)
Hydrogen and Oxygen
True or False: A covalent bond always involves the transfer of electrons. (True/False)
False
Draw the electron dot and cross diagram for H₂. Label the shared pair of electrons.
Two hydrogen atoms, each sharing one electron, forming a bond.
Which of the following is a correct example of a single covalent bond? (H₂, NaCl, MgO)
H₂
Fill in the blank: The bond formed between hydrogen atoms in the molecule H₂ is a ________ bond.
Single covalent
What is the bond formed when two atoms share one electron each to form a pair of electrons?
Single covalent bond
True or False: A single covalent bond involves the sharing of two electrons. (True/False)
True
In the molecule HCl, what type of bond is formed between hydrogen and chlorine?
Single covalent bond
Draw the electron dot and cross diagram for H₂O (water). Label the single bond and the lone pairs.
Oxygen shares electrons with two hydrogen atoms to form a water molecule.
Which of the following is NOT a type of covalent bond? (Single covalent, Double covalent, Ionic bond)
Ionic bond
How many types of covalent bonds exist?
Three
Fill in the blank: A single covalent bond is formed when two atoms share ________ electrons.
One pair of electrons
What is the electronic configuration of a chlorine atom?
2, 8, 7
How does a chlorine molecule (Cl₂) form?
Two chlorine atoms share one electron each to form a molecule.
True or False: Chlorine atoms form a molecule by sharing two electrons. (True/False)
False
How many electrons does a chlorine atom have in its valence shell?
Seven electrons
Fill in the blank: Chlorine atoms share one electron each to form a ________ bond.
Covalent bond
What is the atomic number of carbon?
6
How is a methane molecule (CH₄) formed?
Carbon shares four electrons with four hydrogen atoms to form a molecule.
Which element shares electrons with hydrogen atoms to form methane (CH₄)?
Carbon
True or False: A methane molecule is formed when carbon shares electrons with four hydrogen atoms. (True/False)
True
Fill in the blank: In methane (CH₄), carbon needs ________ electrons to complete its octet.
Four
What is the bond type in the formation of the oxygen molecule (O₂)?
Double covalent bond
How many electrons does an oxygen atom need to complete its octet?
Two electrons
True or False: Oxygen atoms share two electrons each to form a double covalent bond. (True/False)
True
Draw the electron dot and cross diagram for the oxygen molecule (O₂).
Oxygen shares two electrons with another oxygen atom to form a molecule.
How many electrons does a carbon atom share in the formation of carbon dioxide (CO₂)?
Four electrons
What type of bond is formed in carbon dioxide (CO₂)?
Double covalent bond
How many oxygen atoms are involved in the formation of carbon dioxide (CO₂)?
Two oxygen atoms
True or False: Carbon dioxide (CO₂) involves single covalent bonds between carbon and oxygen. (True/False)
False
Fill in the blank: In carbon dioxide (CO₂), carbon forms ________ bonds with two oxygen atoms.
Double covalent
Which molecule is formed when carbon shares four electrons with two oxygen atoms?
Carbon dioxide (CO₂)
Draw the electron dot and cross diagram for carbon dioxide (CO₂).
Carbon shares four electrons with two oxygen atoms to form two double covalent bonds.
Multiple Choice: Which of the following molecules involves a double covalent bond? (O₂, H₂, CH₄)
O₂
Multiple Choice: In the formation of methane (CH₄), what does carbon share electrons with? (Oxygen, Hydrogen, Nitrogen)
Hydrogen
Why do atoms form chemical bonds?
To lower their energy and achieve a stable state.
What is the Octet Rule?
Atoms tend to attain eight electrons in their outermost shell to achieve stability.
What is a Triple Covalent Bond?
A bond in which two atoms share three electrons each, forming a total of six shared electrons.
Which of the following atoms tend to achieve a stable electron configuration by sharing electrons?
A) Oxygen
What type of bond is formed when two atoms share three electrons each?
C) Triple Bond
A Triple Covalent Bond is formed when two atoms share ____ electrons each.
The Octet Rule is achieved when an atom has ____ electrons in its outermost shell.
Atoms always form bonds to increase their energy.
False
Helium is stable with two electrons in its outer shell.
True
What is a covalent bond?
A bond where electrons are shared between atoms to achieve stability.
What happens when atoms form bonds?
They lower their energy and attain stability.
What is a dative bond?
A covalent bond where one atom donates both electrons to form a bond.
What is the Lewis structure of water?
H₂O with two lone pairs of electrons on oxygen and shared pairs between oxygen and hydrogen.
What happens when nitrogen in NH₃ donates a lone pair of electrons?
A) Forms a dative bond
In a dative bond
Covalent bond is formed
A dative bond is also called a ____ covalent bond.
The Lewis structure of H₂S is H-S-H
2
The Nitrogen atom in NH₃ is electron deficient.
False
The Boron atom in BCl₃ is electron deficient.
True
What is a Lewis structure?
A diagram representing shared and unshared electrons in a molecule.
What does a coordinate covalent bond involve?
A bond where one atom donates both electrons.
What is a non-polar covalent bond?
A covalent bond formed by the mutual sharing of electrons between atoms with similar electronegativities.
What is a polar covalent bond?
A covalent bond formed between atoms with different electronegativities, resulting in partial positive and negative charges.
Which molecule forms a polar covalent bond?
A) H₂O
In a polar covalent bond
D) Not shared at all
A non-polar covalent bond is formed when atoms have ____ electronegativities.
In a polar covalent bond
partially negative
In a non-polar covalent bond
The shared electrons in a polar covalent bond are equally shared between the atoms.
False
What is a polar covalent bond?
A bond with unequal sharing of electrons, creating partial charges on the atoms.
Give an example of a non-polar covalent bond.
Molecules like H₂, Cl₂, and O₂ form non-polar covalent bonds.
What is the shape of a carbon dioxide (CO2) molecule?
A) Linear
What is the bond angle in a water (H2O) molecule?
A) 104.5°
Which molecule has a trigonal pyramidal shape?
C) NH3
Which of the following molecules has a bent shape?
A) SO2
The intermolecular forces are __________ times weaker than the covalent bond.
25
Hydrogen bonding occurs when hydrogen is covalently bonded to __________.
All of the above
Intermolecular forces are much weaker in liquid water than in solid water.
False
Dipole-dipole interactions occur due to the attraction between the positive and negative poles of polar molecules.
True
The shape of the methane molecule (CH4) is tetrahedral.
True
Hydrogen chloride (HCl) is a non-polar molecule.
False
Which type of bond involves the sharing of electrons between atoms with similar electronegativities?
B) Non-Polar Covalent Bond
What happens to the electrons in metallic bonding?
C) Electrons move freely between atoms
In which of the following molecules does a polar covalent bond occur?
B) H2O
Which of the following is an example of an ionic bond?
A) NaCl
The bond formed when atoms share electrons equally is called a __________ bond.
Non-Polar Covalent
A molecule of water (H2O) contains a __________ covalent bond.
Polar
In a non-polar covalent bond, the electrons are shared equally.
True
In metallic bonding, electrons are localized and do not move freely.
False
The shape of a methane molecule (CH4) is tetrahedral.
True
In an ionic bond, electrons are shared equally between atoms.
False
What is the shape of a carbon dioxide (CO2) molecule?
“Linear”
What is the bond angle in a water (H2O) molecule?
“104.5°”
Which molecule has a trigonal pyramidal shape?
“NH3”
Which of the following molecules has a bent shape?
“SO2”
The intermolecular forces are __________ times weaker than the covalent bond.
“25”
Hydrogen bonding occurs when hydrogen is covalently bonded to __________.
“All of the above”
Intermolecular forces are much weaker in liquid water than in solid water.
“False”
Dipole-dipole interactions occur due to the attraction between the positive and negative poles of polar molecules.
“True”
The shape of the methane molecule (CH4) is tetrahedral.
“True”
Hydrogen chloride (HCl) is a non-polar molecule.
“False”
Which type of bond involves the sharing of electrons between atoms with similar electronegativities?
“Non-Polar Covalent Bond”
What happens to the electrons in metallic bonding?
“Electrons move freely between atoms”
In which of the following molecules does a polar covalent bond occur?
“H2O”
Which of the following is an example of an ionic bond?
“NaCl”
The bond formed when atoms share electrons equally is called a __________ bond.
“Non-Polar Covalent”
A molecule of water (H2O) contains a __________ covalent bond.
“Polar”
In a non-polar covalent bond, the electrons are shared equally.
“True”
In metallic bonding, electrons are localized and do not move freely.
“False”
The shape of a methane molecule (CH4) is tetrahedral.
“True”
In an ionic bond, electrons are shared equally between atoms.
“False”Question
How strong is a hydrogen bond compared to a covalent bond?
“Hydrogen bond is about twenty times weaker than a covalent bond
Is the hydrogen bond directional?
“Yes
What does hydrogen bonding help in the formation of?
“Hydrogen bonding helps in the formation of networks of molecules.”
What are the properties of ionic compounds?
“Ionic compounds are solid at room temperature
What is the structure of ionic compounds?
“Ionic compounds are composed of cations and anions in crystalline form.”
What happens to the melting point of an ionic compound with greater charges on the ions?
“The melting point increases. For example
How are covalent compounds formed?
“Covalent compounds are formed by the sharing of electrons between atoms.”
Do covalent compounds have high or low melting and boiling points?
“Covalent compounds have low melting and boiling points.”
Are covalent compounds electrolytes in solution?
“No
Are covalent bonds directional?
“Yes
What is the structure of covalent compounds?
“Covalent compounds are composed of molecules.”
How do the reactions of covalent compounds compare to ionic compounds?
“Reactions of covalent compounds are slower than those of ionic compounds.”
Are polar covalent compounds soluble in polar solvents?
“Yes
Are nonpolar covalent compounds soluble in nonpolar solvents?
“Yes
What type of bond holds metals together?
“Metals are held together by metallic bonds.”
Are metals solid at room temperature?
“All metals are solid at room temperature and pressure
Can metals be shaped?
“Yes
Do metals conduct heat and electricity?
“Yes
Are metals shiny?
“Yes
Do metals produce specific sounds when struck?
“Yes
MCQ
What is the shape of a carbon dioxide (CO2) molecule?
MCQ
What is the bond angle in a water (H2O) molecule?
MCQ
Which molecule has a trigonal pyramidal shape?
MCQ
Which of the following molecules has a bent shape?
Fill-in-the-Blank
The intermolecular forces are __________ times weaker than the covalent bond.
Fill-in-the-Blank
Hydrogen bonding occurs when hydrogen is covalently bonded to __________.
True/False
Intermolecular forces are much weaker in liquid water than in solid water.
True/False
Dipole-dipole interactions occur due to the attraction between the positive and negative poles of polar molecules.
True/False
The shape of the methane molecule (CH4) is tetrahedral.
True/False
Hydrogen chloride (HCl) is a non-polar molecule.
MCQ
Which type of bond involves the sharing of electrons between atoms with similar electronegativities?
MCQ
What happens to the electrons in metallic bonding?
MCQ
In which of the following molecules does a polar covalent bond occur?
MCQ
Which of the following is an example of an ionic bond?
Fill-in-the-Blank
The bond formed when atoms share electrons equally is called a __________ bond.
Fill-in-the-Blank
A molecule of water (H2O) contains a __________ covalent bond.
True/False
In a non-polar covalent bond, the electrons are shared equally.
True/False
In metallic bonding, electrons are localized and do not move freely.
True/False
The shape of a methane molecule (CH4) is tetrahedral.
True/False
In an ionic bond, electrons are shared equally between atoms.
MCQ
An atom with a charge is called:
MCQ
Valence electrons are represented by:
MCQ
An element X is in group VI of the periodic table. The ion will be:
MCQ
Which pair of elements will join to form a compound with one-to-one ratio?
MCQ
When a calcium atom becomes a calcium ion (Ca²⁺):
MCQ
Fluorine and oxygen will form:
MCQ
Which two elements will form a covalent compound?
MCQ
In the formation of an ionic bond, the atoms taking part:
MCQ
Fluorine has an electronic configuration 2,7, and Oxygen has 2,6. The formula for the compound formed will be:
MCQ
Which of these statements about covalent bonds is incorrect?
