2.4 Ions and ionic bonds Flashcards
What is the formation of positive ions (cations) and negative ions (anions)?
A cation is a positively charged ion formed when a metal loses an electron. An anion is a negatively charged ion formed when a non-metal gains an electron.
Give an example of a cation.
Sodium (Na) loses one electron to form a sodium ion (Na+), which is a cation.
Give an example of an anion.
Chlorine (Cl) gains one electron to form a chloride ion (Cl-), which is an anion.
What is an ionic bond?
An ionic bond is a strong electrostatic attraction between oppositely charged ions, formed when electrons are transferred from one atom to another.
How does an ionic bond form between a Group I metal and a Group VII non-metal?
The Group I metal loses an electron, becoming a cation, and the Group VII non-metal gains the electron, becoming an anion. For example, sodium (Na) and chlorine (Cl) form sodium chloride (NaCl).
How is the ionic bond in sodium chloride (NaCl) represented using a dot-and-cross diagram?
Sodium (Na) loses an electron (represented by a cross), and chlorine (Cl) gains the electron (represented by a dot). The resulting ions are Na+ and Cl-, which are held together by an ionic bond.
What are the properties of ionic compounds?
Ionic compounds have high melting and boiling points, good electrical conductivity when molten or aqueous, and poor conductivity when solid.
What is the structure of ionic compounds?
Ionic compounds have a giant lattice structure, where positive and negative ions are arranged alternately, held together by strong electrostatic forces.
How do ionic bonds form between metals and non-metals?
Metals lose electrons to form cations, and non-metals gain electrons to form anions. For example, magnesium (Mg) loses two electrons to form Mg2+, and oxygen (O) gains two electrons to form O2-.
How is the ionic bond in magnesium oxide (MgO) represented using a dot-and-cross diagram?
Magnesium (Mg) loses two electrons (represented by crosses), and oxygen (O) gains two electrons (represented by dots). The resulting ions are Mg2+ and O2-, held together by an ionic bond.
Why do ionic compounds have high melting and boiling points?
Ionic compounds have high melting and boiling points because the strong electrostatic forces between oppositely charged ions require a lot of energy to break.
Why do ionic compounds conduct electricity when molten or aqueous but not when solid?
Ionic compounds conduct electricity when molten or aqueous because the ions are free to move. In the solid state, the ions are fixed in place and cannot move to carry charge.
What are other properties of ionic compounds?
Ionic compounds are brittle, have low volatility, and tend to dissolve in water.
