Metal Bonding

Question 1

what are the properties of Metals

Answer 1

they are
* malleable
* ductile
* lustrous
* can conduct heat and electricity

Question 2

what does it mean for metal to be lustrous

Answer 2

Shine or glossiness (reflective quality of a material).

Question 3

what does it mean for metal to be ductile

Answer 3

Ability to be stretched into a wire without breaking.

Question 4

what does it mean for a metal to be malleable

Answer 4

Ability to be hammered into thin sheets without breaking.

Question 5

what does it mean for a metal to conduct heat

Answer 5

Ability to be transfer heat

Question 6

what does it mean for a metal to be able to conduct electricity

Answer 6

Ability to conduct electric current.

Question 7

What is metallic bonding?

Answer 7

Metallic bonding occurs when metal atoms lose outer electrons, which become delocalised, forming a “sea of electrons” around positively charged metal ions (cations).

Question 8

What are delocalised electrons?

Answer 8

Delocalised electrons are free-moving electrons that are not attached to any specific atom and can move throughout the metal, contributing to its properties.

Question 9

What holds the structure of metals together?

Answer 9

The electrostatic attraction between the positively charged metal cations and the negatively charged delocalised electrons holds the structure together.

Question 10

What are metallic crystals?

Answer 10

Metallic crystals are solids where metal atoms are arranged in a regular, repeating pattern (lattice structure), and the atoms are held together by metallic bonds.

Question 11

Name the three common crystal structures of metals.

Answer 11

Body-Centered Cubic (BCC)
Face-Centered Cubic (FCC)
Hexagonal Close-Packed (HCP)

Question 12

What is the Body-Centered Cubic (BCC) structure?

Answer 12

In BCC, atoms are arranged at the corners and center of a cube, with 2 atoms per unit cell.

Question 13

What is the Face-Centered Cubic (FCC) structure?

Answer 13

In FCC, atoms are arranged at the corners and at the center of each face of the cube, with 4 atoms per unit cell. (so an atom in the middle of each face but not one in the dead middle like BCC)

Question 13

What is the Hexagonal Close-Packed (HCP) structure?

Answer 13

In HCP, atoms are arranged in a hexagonal pattern, with 6 atoms per unit cell.

Question 14

Why do metals conduct electricity?

Answer 14

Metals conduct electricity because the delocalised electrons in the metallic bonding model are free to move throughout the structure, allowing them to carry charge when a potential difference is applied.
(* If a current/ potential difference is applied, electrons are forced in at one end and an equal number flow out the other end, hence producing a current.)

Question 15

Why are metals malleable and ductile?

Answer 15

Metals are malleable and ductile because the layers of metal atoms can slide past each other without breaking the metallic bonds, thanks to the delocalised electrons holding the structure together.
( When re-arranging a metal, the positive ions are forced across each other. The delocalised electrons also move to compensate. )

Question 16

Why do metals conduct heat well?

Answer 16

Metals conduct heat well because the delocalised electrons move quickly, transferring energy throughout the metal and allowing heat to spread efficiently.

Question 17

Why do metals have high melting and boiling points?

Answer 17

Metals have high melting and boiling points because a large amount of energy is required to overcome the strong electrostatic attraction between the metal cations and the delocalised electrons.
(In general, the higher the charge, the stronger the attraction and hence the higher the melting point)

Question 18

Why are metals strong and hard?

Answer 18

Metals are strong and hard due to the strong metallic bonds between cations and delocalised electrons, as well as the regular arrangement of atoms in the lattice structure.

Question 18

why are metals lustrous

Answer 18

Light can be reflected due to the presence of free moving delocalised electrons

Question 19

why are metals generally dense?

Answer 19

positive ions are closely packed

Question 20

Why are some metals more reactive than others?

Answer 20

Size of the charge on the ion
Distance of valence electrons from the nucleus

Question 21

Example: Why is sodium more reactive than magnesium?

Answer 21

Sodium (Na) has a larger atomic radius and only one electron in its outer shell, which is far from the nucleus. This makes it easier for sodium to lose that electron because it requires less energy to lose the valence eletron. While Magnesium (Mg), on the other hand, has two valence electrons that are closer to the nucleus, making it harder for magnesium to lose electrons due to needing more energy and thus making it less reactive than sodium.

Question 21

How does the distance of valence electrons from the nucleus affect reactivity?

Answer 21

If valence electrons are farther from the nucleus (as in metals with a larger atomic radius), the attraction between the nucleus and the electrons is weaker. This makes it easier for the atom to lose its outer electrons, increasing the metal’s reactivity.

Question 21

How does the size of the charge affect reactivity?

Answer 21

Metals with a higher charge (more protons) tend to hold their valence electrons more tightly, making it harder for them to lose electrons. This generally reduces reactivity. Conversely, metals with a lower charge (fewer protons) have weaker attraction between the nucleus and the valence electrons, making it easier for the metal to lose electrons and become more reactive.

Question 22

what is ionisation energy

Answer 22

minimum energy required to remove the most loosely bound electron

Question 23

what is sustainablity/ replacement

Answer 23

A chemical/product is sustainable if it can be produced at a rate that is greater than or equal to the rate of consumption without compromising future generations

Question 24

what are the 3 e's of sustainability

Answer 24

environmental social economic (finding the balance between the 3 so that there can be a health equilbrium, so not too much of one and not the other)

Question 25

What is a circular economy?

Answer 25

A circular economy is an economic system where resources are used, reused, and recycled, aiming to minimize waste and make the most of existing materials. It contrasts with the traditional "linear economy," which follows a "take, make, dispose" model.

Question 26

How does a circular economy apply to metal recycling?

Answer 26

* Reusing metal products: Metals can be reused repeatedly without degrading their quality, such as using aluminum or steel in new products. * Recycling scrap metal: Old metal products (like vehicles or electronics) are melted down, purified, and reformed into new products, reducing the need for mining new metals. * Reducing waste: Instead of discarding metal waste, it is collected, recycled, and reused, reducing the environmental impact of extracting and processing raw metal. * Saving energy and resources: Recycling metals consumes less energy compared to mining and refining new metals, conserving natural resources and reducing carbon emissions.

Question 26

Key Principles of a Circular Economy

Answer 26

Reduce: Minimize resource consumption and waste. Reuse: Use products or materials again for the same or new purposes. Recycle: Process materials to create new products, reducing the need for raw resources. Repair: Extend the life of products by fixing them rather than discarding them.

Question 27

Benefits of Metal Recycling in a Circular Economy

Answer 27

* Conservation of natural resources: Reduces the need to mine for new metals, protecting ecosystems and preserving natural habitats. * Energy savings: Recycling metals, like aluminum, uses much less energy than producing new metal from raw ores. * Reduction in pollution: Less waste and fewer emissions from mining and processing metals. * Economic benefits: Recycling creates jobs in the collection, processing, and manufacturing industries.