REVIEW: Parts of the Atom

ElectronElectron

OrbitOrbit

NeutronNeutron

ProtonProton

NucleusNucleus

Element, Compound, or Mixture?

ELEMENTELEMENT COMPOUNDCOMPOUND ELEMENTELEMENT

MIXTUREMIXTURE COMPOUNDCOMPOUND MIXTUREMIXTURE

Review of the Periodic Table

titanium22

47.867

What is the symbol for Titanium?

_________

What is the atomic number of titanium?

_________

How many protons does titanium have?

_________

How many electrons does a neutral titanium atom have?

__________

What is the atomic weight for titanium?

_______________

Ti

Ti

22

22

47.867

22

Author: J R Reid

The Periodic Table

The Periodic table as we know it today was arranged by a Russian Chemist named Mendeleev. He arranged it according to the physical and chemical properties of the elements

WORKSHEET 1

Complete the handout by writing the missing chemical symbols in each box.

ON your periodic table (given last lesson) Label the following:

AlkaliAlkaline MetalsTransition MetalsPoor metalsHalogensNoble gasesNon metals

halogens

Arranging Elements

It is arranged in rows (across) called Periods and columns (down) called Groups

Groups of elements show certain trends – they have similar properties

Groups

Periods

Author: J R Reid

Trends On The Periodic Table

Atomic Size

Atoms have certain sizes depending on:The amount of electrons (negatives)The pull from the nucleus (positive protons)

For the third period (row) the atomic radius for each atom gets smaller across the table

Even though the atoms have got more electrons their electronegativity (pull for electrons) is increasing because of increasing number of protons

Na Mg Al Si P S Cl Ar

Na Mg Al Si P S Cl Ar

Electronegativity

Electronegativity is the ability of a nucleus to attract its valence/bonding electrons. It follows certain trends on the table:

As you go across (left to right) it gets strongerAs you go up it gets stronger

e-e-

e- e-

e-e-

e-

e-

e-

e-

e-

e-e-

e-

e-11 12 13 14 15 16 17

K

e-

e-

e-

e-

e-

e-

e-

e-

What do you notice about the atomic number as you go across the period?

What about the number of orbitals as you go across the period?

What about the number of orbitals as you go down a group?

19

Increasing size Size

Trends From Left to Right

Proton number and Atomic Mass increasesAtomic size decreases (more protons pulling the electrons)

Oxidising ability increasesForm ionic compounds to forming covalent compoundsMelting Points from relatively high to relatively low Form positive ions to form negative ions

Trends down a group

Proton number and Atomic Mass increasesAtomic size increases (adding more orbitals)Metals become more reactiveNon-metals become less reactive

Valence Electrons

Valence electrons (also known as valence) are the number of electrons present in the outer most orbital.

What is the valence of this sodium atom?

What is the valence of this chorine atom?

Valence Electrons

The number of valence electrons of an element is determined by its periodic table group in which the element is categorized.