Chemical Bonding and Structure - Topic 4

What are cations?

Positive ions formed by metals losing valence electrons

What are anions?

Negative ions formed by non-metals gaining electrons

What determines the number of electrons lost/gained?

The electron configuration of the atom

What causes ionic bonding?

Electrostatic attraction between oppositely charged ions

What traits do ionic compounds have under normal conditions?

They are solid and have lattice structures and display non-volatile properties, are conductors when aqueous or molten, have low boiling and melting points, and are soluble in polar substances

How is a covalent bond formed?

The electrostatic attraction between a shared pair of electrons and the positively charged nuclei

How many pairs of electrons do single, double, and triple bonds share respectively?

one, two, and three

What is the relationship between bond **length** and the number of shared electrons?

As the number of shared electrons increases, bond length decreases

What is the relationship between bond **strength** and the number of shared electrons?

As the number of shared electrons increases, bond strength increases

What is bond polarity?

The partial charge in compounds caused by the difference in electronegativities of bonded atoms

What are Lewis structures?

Representations of all the valence electrons in a covalently bonded species

What is the octet rule?

The tendency of atoms to gain a valence shell with a total of eight electronsWh

Which elements may form incomplete octets whilst being stable?

Beryllium (Be) and boron (B)

What is resonance structure?

A structure that represents more than one possible position for a double bond in a molecule

What is VSEPR?

Valence shell electron pair repulsion: the determination of the shape of species according to the repulsion of electron pairs

Which two elements can form covalent network (giant covalent) structures?

Carbon (C) and silicon (Si)

#### How relaxed is this boy?

He is a very relaxed boy

What are the different types of intermolecular forces?

London dispersion forces, dipole-dipole forces, and hydrogen bonding

What is the relative strength of the intermolecular forces from weakest to strongest?

London dispersion forces < dipole-dipole forces < hydrogen bonds 💪

What is a metallic bond?

The electrostatic attraction between a lattice of positive ions and delocalized electrons

What determines the strength of a metallic bond?

The charge of the ions and the radius of the metal ion

What are alloys?

Compounds that contain more than one metal and have enhanced properties