Chemistry - Atomic Theory

Periodic table

a display of chemcial elements

groups

• the vertical rows (numbered 1 to 18)

• elements have similar properties and have the same number of electrons in their outer shell

periods

• the horizontal rows (numbered 1 to 7)

• elements have the same number of shells occupied by its electrons

What are the three major groups the elements are divided into?

Metals, Non-metals and Metalloids

Which side are Metals on the periodic table?

Left-hand side

Where are Metalloids on the periodic table?

Small set of elements in between metals and non-metals

Which side are Non-metals on the periodic table?

Right-hand side

What are Metals characteristics?

Lustrous , Malleable and Ductile

Lustrous

Shiny surface

Malleable

Can be beaten into shapes

Ductile

Can be drawn out into wires

Which group have a high melting and boiling point?

Metals

What are Metalloids characteristics?

Exhibits properties of metals and non-metals (only 6 elements)

What are Non-metals characteristics?

Dull and Brittle, not Lustrous and not Ductile

Dull

lack a shiny, reflective surface or a metallic luster

Brittle

breaks easily

Which group are good conductors of heat and electricity?

Metals

Which group have a low melting and boiling point?

Non-metals

Which group are poor conductors of heat and electricity?

Non-metals

Transition metals

The block containing the elements in groups 3 to 12 and in periods 4 to 7.

What are Transition metals characteristics?

Hard and dense but chemical reactivity varies

Where are Lanthanoids and actinoids on the periodic table?

Metals that sit at the bottom of the periodic table.

What are Lanthanoids?

rare earth elements (found in period 6)

What are actinoids?

they are mostly unstable (found in period 7)

What are atoms?

the basic building block of all matter.

• they are neutral (same number of protons and electrons)

What are the subatomic particles in an atom?

Proton, Neutron and Electron

What charge are protons and where is it found?

Positive charge and found in the nucleus

What charge are neutrons and where is it found?

Neutral charge and found in the nucleus

What charge are electrons and where is it found?

Negative charge and found orbiting around the nucleus

What does the atomic number tell us?

The number of protons

What does the mass number tell us?

The amount of protons and neutrons (everything in the nucleus)

in a neutral atom, number of protons is equal to …

number of electrons

What is an isotope?

An isotope is the same element with a different mass (different neutrons)

What are charged atoms called?

Ions

What makes an atom charged?

when the atom loses or gains electrons

What are the two types of ions?

Anions and Cations

What are anions?

Negatively charged ions (atoms gain electrons)

What are cations?

Positively charged ions (atoms lose electrons)

Cat (ion)

Cat = paw so pawsivite charge

Why do atoms from ions?

Atoms from ions because ions are more stable.

• Ions also need to have a full valence shell

for that to happen

• Metals lose elections to from cations

• Non-metals gain electrons to from anions

What is the valence shell?

the outer-shell electron of an atom

How to know the number of electrons gained or lost?

It depends on the number of valence electrons that the atom has.

What are valence electrons?

The electrons located in the outermost shell of an atom.

What is bonding?

When compounds form when different atoms react or join together.

What are the 3 main ways atoms may join together?

Ionic bonding, Covalent bonding and Metallic bonding.

What is Ionic Bonding?

when atoms or groups of atoms lose or gain electrons

• when a positive cation and negative anion come close together to each other, they attract.

• an electrostatic attraction between charged ions

What is Covalent bonding?

a strong bond almost always between two non-metals that share electrons, forming a molecule.

What is Metallic bonding?

it is the force of attraction between valence electrons and metal atoms.

What does an Electron transfer diagram show?

shows how electrons transfer from metals to non-metals to form an ionic compound.

What is the overall charge of an ionic compound?

Zero (charges cancel out)

What is Electron configuration?

How the electrons are organised around the nucleus of an atom.

How are electrons arranged around the nucleus?

Each electron is placed on a particular electron shell that have different energy levels.

How many electrons in the 1st shell?

2 electrons

How many electrons in the 2nd shell?

8 electrons

How many electrons in the 3rd shell?

8 electrons

How many electrons in the valance shell (4th shell/ outer shell)?

2 valance electrons

What can valance electrons do?

they are able to interest with other atoms to form chemical bonds

Group 1

Alkali Metals

Group 17

Halogens

Group 18

Noble Gases

What are Alkali Metals characteristics?

Soft and can be cut with a knife, shiny appearance on the inside compared to dull outer surface.

Alkali metals are highly reactive …

with reactivity increasing down the group

What is formed when an alkali metal reacts with water?

forms an alkaline solution

What forms when Alkali metals and group 17 elements react?

Forms white salts

Group 2

Alkaline Earth Metals

What are Alkaline earth metals?

Shiny an silvery white

• not as reactive as group 1 elements

Are alkaline earth metals have a high or low melting and boiling point?

Low

What is formed when an alkaline earth metal reacts with water?

forms an alkaline solution

What forms when Alkaline earth metals and group 17 elements react?

forms metal salts

What forms when Alkaline earth metals and oxygen react?

forms metal oxides

Group 17

Halogens

At room temperature what two characteristics vary?

the states and colours

What are Halogen elements used for?

used as bleaching agents and can kill bacteria

How many valence electrons do Halogens have?

7

What charge of ions do Halogens form?

Forms ions with a charge of -1

As you move down the group what does the reactivity and boiling points do?

Reactivity decreases and boiling points decrease

Group 18

Noble Gases

What are the characteristics of Noble gases?

Colourless, odourless and non-flammable

Are Nobel gases reactive?

No, they are extremely unreactive

Where are noble gases used?

Medical imaging and radiotherapy