Exam Revision Flashcards
Explain covalent bonding
When non-metal atoms combine and form either a molecule or covalent lattice. It is a chemical link between two atoms or ions where electron pairs are shared to stabilize valence electron shell.
explain the model of metallic bonding
When metal atoms combine and form a metallic lattice. Consists of positive ions (cations) in a ‘sea’ of delocalized electrons
explain ionic bonding
ionic bonding is when metal atoms combine with non-metal atoms and an ionic lattice is formed. It is a type of chemical bonding that involves the electrostatic attraction between anions and cations.
Why are some ionic compounds soluble in water while others aren’t?
Water has the ability to dissolve many ionic compounds, meaning water molecules can pull apart the ionic lattice and surround each ion. Solubility depends on water overcoming the electrostatic forces between the ions. But some ionic compounds are insoluble due to the high ionic forces in the molecules, creating high lattice energy.
Explain how ionic compounds from crystal lattice structures
Ionic compounds form crystal lattice structures at room temperature due to the strong electrostatic forces between the positively charged cations and negatively charged anions. These ions are formed when atoms of metals lose electrons and become positively charged, while atoms of non-metals gain these electrons and become negatively charged. The resulting cations and anions are then drawn together by their opposite charges.
In a crystal lattice, each ion is surrounded by ions of the opposite charge, creating a stable and orderly arrangement. This structure is highly efficient because it maximizes the attractive interactions between ions while minimizing the total intermolecular energy
similarities and differences between ionic lattices and metallic lattices
Ionic lattices and metallic lattices are both types of crystalline structures that form in solid materials, but they have distinct characteristics due to the nature of the bonding and particles involved.
Similarities:
Both ionic and metallic lattices typically have high melting points due to strong electrostatic forces in ionic lattices and strong metallic bonding in metallic lattices.
They both form ordered, three-dimensional arrangements that extend throughout the material.
The stability of both lattices is due to electrostatic forces; in ionic lattices, it’s the attraction between oppositely charged ions, and in metallic lattices, it’s the attraction between positive metal ions and delocalised electrons12.
Differences:
Ionic lattices consist of cations and anions arranged in a repeating pattern, while metallic lattices consist of metal cations surrounded by a ‘sea’ of delocalised electrons.
Bonding Nature: Ionic bonding is the force holding ionic lattices together, resulting from the attraction between oppositely charged ions. Metallic bonding, on the other hand, is due to the attraction between metal cations and the delocalised electrons that move freely around them.
Electrical Conductivity: Ionic compounds typically do not conduct electricity in their solid state because the ions are fixed in place within the lattice. Metals, however, are good conductors of electricity due to the free movement of delocalised electrons within the lattice2.
Malleability and Ductility: Metals are malleable and ductile because the layers of ions in a metallic lattice can slide over each other without breaking the metallic bond. Ionic lattices are brittle and tend to shatter when force is applied because shifting layers of ions bring like charges into close proximity, repelling each other and causing the lattice to fracture2.
Thermal Conductivity: Metals are generally good thermal conductors because of the free electrons that can transfer kinetic energy. Ionic lattices, lacking free-moving charges in their solid state, are usually poor conductors of heat2.
These properties result from the fundamental differences in the types of particles and the nature of bonding in ionic and metallic lattices, leading to their unique physical characteristics.
lone pair of electrons
A lone pair of electrons is a set of two valence electrons that are not involved in bonding with another atom; they are also known as a non-bonding pair. These electrons are located in the outermost electron shell of an atom.
how do lone pairs influence the 3D shape of molecules
Lone pairs of electrons significantly influence the three-dimensional shape of molecules by affecting the distribution of electron density and the spatial arrangement of atoms. Electron pairs, whether they are in bonds or are lone pairs, repel each other. This repulsion causes the molecule to adopt a shape that minimizes the repulsion and maximizes the distance between all pairs of electrons
Explain metal reactivity and how it relates to the electrochemical series
Metal reactivity refers to the tendency of a metal to undergo a chemical reaction, particularly with respect to how easily a metal can lose electrons to form positive ions (cations). This reactivity is often showcased in the reactivity series of metals, which ranks metals from most to least reactive.
Metals that donate only one electron to form stable ions are generally more reactive than those that donate more than one electron.
Why is there always oxidation and reduction
In a redox (reduction-oxidation) reaction, there is always both oxidation and reduction occurring simultaneously due to the transfer of electrons between reactants. Since electrons cannot exist freely in solution, they must be transferred from one substance to another. Therefore, if one substance is oxidized (loses electrons), another must be reduced (gains those electrons).
Explain how a galvanic cell works
A galvanic cell, also known as a voltaic cell, works by harnessing the energy from spontaneous redox (reduction-oxidation) reactions to generate electrical energy. a galvanic cell transforms chemical energy into electrical energy through redox reactions1. This is the basis for batteries and many other types of electrochemical cells.
Learn more
1
chem.libretexts.org
2
en.wikipedia.org
3
byjus.com
4
toppr.com
5
khanacademy.org
6
sparknotes.com
7
gettyimages.com
+5 more
What does ICEAGE stand for
Inherited variation exists within the population
Competition results from an overproduction of offspring
Environmental pressures lead to differential reproduction
Adaptations which benefit survival are selected for
Genotype frequency changes across generations
Evolution occurs within the population
