Unit 4: Chemical Bonding & Tetra Covalency of Carbon Flashcards
What characterizes ionic bonding?
Ionic bonding is formed between a metal and a nonmetal through the transfer of electrons.
What is a pi bond and how is it formed?
A pi bond is formed between atoms already connected by a sigma bond.
What is a chemical bond?
A mutual electrical attraction between the nuclei and valence electrons of different atoms.
How is a covalent bond formed?
A covalent bond forms when two or more nonmetal atoms share electrons.
What is the key difference in bond formation between sigma and pi bonds?
Sigma bonds are formed by axial overlap, while pi bonds are formed by sideways overlap of atomic orbitals.
What defines a metallic bond?
A metallic bond is formed by the attraction between metal cations and delocalized electrons.
What defines bond length in covalent bonds?
Bond length is the distance between bonded atoms at their minimum potential energy.
What are valence electrons?
The outermost electrons of an atom available for losing, gaining, or sharing in chemical bonds.
What is a sigma bond?
A sigma bond is formed by mutual overlap of atomic orbitals, characterized by maximum overlap.
Why can’t a pi bond exist without a sigma bond?
A pi bond is an additional bond that requires a sigma bond to already be present.
What is a hydrogen bond?
A hydrogen bond is an attraction between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.
What types of atoms form ionic bonds?
Ionic bonds are formed between a metal and a nonmetal.
How are ionic bonds formed?
Through the transfer of valence electrons between a metal cation and a non-metal anion.
How is bond energy expressed and what does it represent?
Bond energy is measured in kJ/mol and represents the energy needed to break a chemical bond.
What is the impact of sigma bonds on atom rotation?
Sigma bonds allow free rotation of atoms around the bond axis.
Which atoms commonly participate in hydrogen bonds?
Common atoms are oxygen, nitrogen, or fluorine, which carry a partial negative charge.
What kind of orbitals overlap to form a hydrogen molecule?
A hydrogen molecule (H₂) is formed by the overlap of half-filled s-orbitals.
How do non polar covalent bonds differ from polar covalent bonds?
Non polar bonds share electrons equally, while polar bonds do not.
What defines a covalent bond?
A covalent bond is defined by the mutual sharing of electrons between two atoms.
What are key properties of ionic bonds?
Ionic bonds are hard, with high melting and boiling points, and are brittle.
What distinguishes the strength of sigma and pi bonds?
Sigma bonds are stronger due to significant overlap, whereas pi bonds are weaker due to less extensive overlap.
What defines metallic bonding?
Metallic bonding involves the electrostatic attraction between positively charged ions and delocalized outer electrons.
How is a pi bond formed?
A pi bond is formed by the sideways overlap of half-filled p-orbitals.
What are the three types of covalent bonds based on shared electron pairs?
The three types are single, double, and triple covalent bonds.
What are the characteristics of melting and boiling points in covalent compounds?
Covalent compounds typically have low melting and boiling points, often existing as liquids or gases at room temperature.
What is electronegativity, and how does it trend in the periodic table?
Electronegativity measures electron attraction, increasing across a period and decreasing down a group.
What is the definition of a molecule?
A group of covalently bonded atoms.
How is a hydrogen molecule (H₂) formed?
A hydrogen molecule forms when two hydrogen atoms share electrons, creating a covalent bond.
What is an example of ionic bonding involving sodium and chlorine?
Sodium (Na) loses one electron to chlorine (Cl), forming oppositely charged ions that create a crystal structure.
What is the structure of a hydrogen atom?
Each hydrogen atom has one electron located in the 1s orbital.
What distinguishes sigma bonds from pi bonds?
Sigma bonds involve head-on overlap and are stronger, while pi bonds involve lateral overlap.
Why do covalent compounds not conduct electricity?
Covalent compounds do not conduct electricity in fused states or solutions due to lack of ions.
What typically causes covalent bonding?
Covalent bonding occurs when elements share pairs of valence electrons, typically between non-metal elements.
Why do atoms prefer to bond in terms of potential energy?
Atoms favor bonding as it results in lower potential energy.
How do hydrogen atoms form a covalent bond?
Covalent bond formation occurs as overlapping electron clouds release energy between two approaching hydrogen atoms.
What role does low ionization energy play in ionic bonding?
It allows an atom to readily lose electrons, facilitating the formation of cations necessary for ionic bonds.
What defines the strength of sigma bonds?
Sigma bonds have maximum overlap, making them strong; all single bonds are classified as sigma bonds.
What is Pauli’s Exclusion Principle?
An orbital can hold a maximum of two electrons with opposite spins.
What is the basis of valence bond theory in covalent bonding?
Covalent bonds form from overlapping half-filled atomic orbitals with electrons of opposite spins.
How do different types of covalent bonds differ?
Single bonds share one pair, double bonds share two pairs, and triple bonds share three pairs of electrons.
Why is high electron affinity important in ionic bonding?
High electron affinity helps an atom gain electrons easily, forming anions which are essential for ionic bonds.
What determines the strength of a covalent bond?
The strength increases with larger overlap of atomic orbitals during bonding.
What distinguishes a sigma bond from other covalent bonds?
A sigma bond is formed by head-on overlap and is the strongest type of covalent bond.
How does lattice energy influence the strength of ionic bonds?
Higher lattice energy, resulting from strong electrostatic attractions, leads to stronger ionic bonds between ions.
What factors influence lattice energy in ionic bonding?
The size and charge of ions; smaller size and higher charge increase lattice energy and bond strength.
