- Rutherford - Positive nucleus is orbited by electrons.

Atoms, Bonding & Structures F4 Flashcards by Denise Gaspar

Plum Pudding Model

Thomson

- Electrons are dotted through a positively charged sphere.

How well did you know this?

Not at all

Perfectly

Modern Model of Atom

Rutherford

- Positive nucleus is orbited by electrons.

How well did you know this?

Not at all

Perfectly

Who discovered neutron?

Chadwick

- Neutral

How well did you know this?

Not at all

Perfectly

Atom

Simplest part of element that can exist and take part in chemical reactions.

How well did you know this?

Not at all

Perfectly

Element

Pure substance which contains only one type of atom.

How well did you know this?

Not at all

Perfectly

Compound

Pure substance which contains two or more elements chemically combined.

How well did you know this?

Not at all

Perfectly

Mixture

Substance which is not chemically combined and can be easily separated.

How well did you know this?

Not at all

Perfectly

What does the number is electrons in outermost shell indicate?

Group number.

How well did you know this?

Not at all

Perfectly

Isotopes

Atoms with the same atomic number but different mass number.

How well did you know this?

Not at all

Perfectly

Ions

Charged particles formed when an atom either loses or gains electrons.

How well did you know this?

Not at all

Perfectly

What are CATIONS?

Positively charged ions.

How well did you know this?

Not at all

Perfectly

What are ANIONS?

Negatively charged ions.

How well did you know this?

Not at all

Perfectly

What is the radius of an atom?

0.1nm

How well did you know this?

Not at all

Perfectly

1nm =

= 1 x 10-9m

How well did you know this?

Not at all

Perfectly

Radius of nucleus

1/10,000

How well did you know this?

Not at all

Perfectly

Alloy

Mixture of 2 or more elements, at least one of which is a metal.

Has metallic properties.

How well did you know this?

Not at all

Perfectly

What is steel an alloy of?

Iron and Carbon.

Bonding

How atoms / ions are held together

Structure

How atoms / ions are arranged

Metallic Structure

METALLIC BONDING
Attraction between positive ions and delocalised electrons. 
- High melting and boiling points 
   (attraction between positive ions and delocalised electrons) 
- Good conductors 
   (delocalised electrons)
- Malleable (can be hammered into shape)
- Ductile (can be drawn into wire)

Giant Ionic Lattice Structure

IONIC BONDING
Ionic attraction between oppositely charged ions.
- High melting and boiling points
(substantial amount to break bonds of oppositely charged particles)
- Good conductors
- Soluble
SODIUM CHLORIDE

Molecular Covalent Structure

COVALENT BONDING
(O2, H2O, NH3)
- Strong covalente bonds
- Low melting and boiling points
   (weak Van de Waals’ forces between molecules)
- Don’t conduct
   (molecular covalent have neutral particles)
- Insoluble

Giant Covalent Structure

COVALENT BONDING
- 3D structure joined by covalent bonds 
- Large continuous networks of covalently bonded atoms 
• Diamond
• Graphene
• Graphite
- All made of Carbon

Allotropes

Different forms of the same element in the same state.

Diamond

- Each carbon atom covalently bonded to 4 others - Very hard due to strong covalent bonds - Very high melting and boiling points because of covalent bonds - Doesn’t conduct (no free ions / delocalised electrons)

Graphite

- Most common form of Carbon - Layers of Carbon atoms arranged in hexagons - Weak Van de Waals’ forces between layers - One electron per carbon atom is unbonded (delocalised electrons) - Soft because layers can slide past each other due to weak Van de Waals’ forces - Good conductors (unbonded electron)

Graphene

- One atom thick layer - Strong Covalent bond between each atom - Very high melting and boiling points (substantial energy) - Very strong due to strong covalent bonds - Good conductor as one electron per carbon atom is unbonded (delocalised electrons)

Ionic Bonding

- Metal & Non-Metals - Electrons transfer from metal to non-metal - Opposite charged ions attract to form large regular structures.

Covalent Bonding

- 2 or more non-metal atoms, sharing electron pairs - Uncharged particles due to no ions - Shared electrons attract nucleus of atom

Molecule

Two / more atoms covalently bonded together.

Diatomic

Two atoms covalently bonded in molecule.

Lone pair of electrons

2 / more unbonded electrons in molecules.

Metallic Bonding

- Attraction between positive metal ions in regular lattice and delocalised electrons

Delocalised electrons

Electrons that are free to move throughout the whole structure.

Covalent Bonds

One pair - SINGLE covalent Two pairs - DOUBLE covalent Three pairs - TRIPLE covalent

What is used in ALLOYS?

Gold Silver Copper Zinc

How to find % of gold?

% = no. of carats/24 x 100

How to find amount of carats (K)?

K = % x 24 / 100

Nanoparticles

Structure that is 1-100nm in size and contain a few hundred atoms.

Surface Area to Volume Ratio

As the size of a cube increases, the surface area to volume ratio decreases.

Benefits of Nanoparticles

- Better skin coverage to sun cream - More effective protection - Clear and colourless - Does not degrade on exposure to sun

Major Risks of Nanoparticles

- Harmful effects on humans & environment - Potential cell damage in body - More reactive / more toxic than bulk material