1. Unit 9 – Classification of Matter and Periodic Trends
Matter and change of matter is classified by form and available evidence
The Periodic Table's function as a technological model is to illustrate repeating patterns among elements and provide structure and information at the heart of modern chemistry

2. What is Matter?
mass
Matter is anything that has ___________ and takes up ___________.
What are some examples of matter? ____________________________________________________________________
Is light matter? _______________
Is wood matter? _______________
Is air matter? ______________
space No
Yes
Yes

3. Classifying Matter
All matter can be classified into one of several groups based on the properties of the substances.
__________________ are substances that are made up of only one type of particle.
Pure substances have a _______ composition
_______________ and _________________ are pure substances
Pure Substances
fixed
Elements
compounds

4. Classifying Matter – Elements
Elements cannot be broken down into simpler substances through __________ or _______________ processes.
Elements are made of atoms.
________ are the smallest particles that still have the properties of that element.
Atoms join together to form ____________.
chemical
physical
Atoms
compounds

5. Classifying Matter – Compounds
__________________ can be broken into the atoms that make them up through chemical processes.
Compounds are unique and different from the _____________ they contain.
Water is a compound made of _____________ and _____________.
The smallest unit of a compound is called a ________________.
elements
hydrogen
oxygen
molecule ?

6. Classifying Matter – Mixtures
Mixtures vs. pure substances
A _________________ is matter that has a fixed composition and cannot be broken down or separated by a physical change.
A ________________ is a combination of two or more pure substances that can be separated by a physical change.
pure substance
mixture

7. Classifying Matter – Mixtures
Mixtures are classified by how well they mix
____________________ mixtures are not uniformly mixed and do not look the same throughout.
One example is flour mixed with water. The mixture looks like muddy water.
____________________ mixtures look the same throughout.
An example would be salt water.
Heterogeneous
Homogeneous

8. Classifying Matter – Mixtures
______________ liquids are able to dissolve into each other, and form a homogeneous mixture.
__________________ liquids are heterogeneous and form layers of liquid.
Gases can also mix with liquids
Miscible
Immiscible

9. Classifying Matter – Mixtures
Homogeneous Mixtures are known as _______________
There are two types of heterogeneous mixtures
Suspensions and Colloids
_________________ have large particles that will settle out of the mixture
_________________ have particles that are smaller and do not settle out.
solutions
Suspensions
Colloids

10. Elements Compounds Matter Mixtures Pure Substances Heterogeneous
Homogeneous

11. Physical and Chemical Properties
A ______________ property is the way a substance reacts to form new substances with different properties.
___________ is the ability of a substance to combine chemically with other substances.
Examples of Chemical Properties
_____________________________________________
Reactivity

12. Physical and Chemical Properties
Physical properties are characteristics of a substance that can be observed or measured without changing the ___________________ of the substance.
Ex. ________________________________
Ex. _____________________________________
composition

13. Physical and Chemical Changes
A ___________________ change occurs when a substance changes composition by forming one or more new substances.
Referred to as chemical reactions
Ex. ____________________________________
Chemical changes occur when the atoms are either broken apart from each other or _______________ to form new substances
The atoms do not change their ___________
rearranged
identities

14. Physical and Chemical Changes
Physical changes do not change the ________________ of the substance.
The substance may look different, but it is still made of the same substances.
Ex. ____________________________________
_______________ is a physical change.
Salt water tastes the same as table salt, because the ________________ of the salt does not change when dissolved.
composition
Dissolving
composition

15. Periodic chemical properties
electron
Understood in terms of _____________ ________________
Electrons in outer orbits determine _____________ properties
Outer electrons are called ______________ electrons
Determines how an atom interacts with other ____________
configuration
chemical
valence
elements

16. The Periodic Table periods groups Alkali metals Alkaline Earth metals
Rows = _____________ (left to right)
Columns: families or __________ (up & down)
__________________ (Group 1 or IA)
____________________ (Group 2 or IIA)
__________________ (Group 17 or VIIA)
__________________ (Group 18 or VIIIA)
A-group families = main group or ________________ elements
___ -group = transition elements or metals
groups
Alkali metals
Alkaline Earth metals
Halogens
Noble gases
representative B

17. The periodic table

18. Metals, nonmetals and semiconductors
What makes an element a metal?
A substance that has a tendency to lose ____________ to empty its valence shell.
What makes an element a nonmetal?
A substance that has a tendency to gain ____________ to fill its valence shell.
A few elements exhibit properties of both metals and nonmetals.
These elements are called ________________ or ___________________
electrons
electrons
metalloids
semi-conductors

19. Metals, nonmetals and semiconductors
stable elements
Noble gases - filled shells, _____________
1A, 2A, & 3A Groups
Lose outer electrons to become _______________ ions - ___________
All elements in these groups are ________
5A, 6A & 7A Groups
Tend to ____________ electrons and form negative ions - _____________
All elements in these groups are __________
_________________ - intermediate between metals and nonmetals
cations
positive
metals
gain
anions
nonmetals
Semi-conductors

20. Metals, nonmetals and semiconductors

21. Periodic Trends
Properties of the elements exhibit periodic trends, i.e. these properties repeat themselves as you go across the ____________ of the Periodic Table
Known as the __________________
Elements are organized by their __________ properties and give the organization to the Periodic Table
periods
Periodic Law
repeated

22. Atomic Radius
Generally, the atomic radius decreases across a period from left to right and increases down a given group

23. Relative Atomic Radii

24. Periodic Trends valence larger attraction smaller
Shielding Effect : the ability of the core (inner) electrons to repel the ____________ (outer) electrons. It makes the atom _____________.
Nuclear Force of Attraction: this is the electrostatic force of ______________ that exists between protons and electrons. It makes the atom ________.
valence
larger
attraction
smaller

25. Periodic Trends protons
Remember, _______________ are increasing one at a time moving from left to right across a period
As this happens, the electrons of the outermost shell experience increasingly strong nuclear attraction – electrons become __________ to the nucleus
The increased number of protons going across a given period increase the pull of the outer shell electrons – the atom ___________________
Going down a group, each new element represents a new _________ of electrons and thus a larger atom
closer
becomes smaller
shell

26. Ionization Energy
The ionization energy is the energy required to completely remove an ____________ from a gaseous atom
The closer an electron is to the ___________, the more difficult it will be to remove
- means _________ ionization energy
Ionization energies increase moving from left to right across a _____________ (decreasing atomic radius) and decrease moving down a __________ (increasing atomic radius)
electron
nucleus
greater
period
group

27. Periodic Trends ionization
Metals have lower _______________ energies than non-metals that share their period or group.
The easier it is for ___________ to lose their valence electrons the more _______________they will be.
Non-metals have higher ionization energies than _________ that share their period or group. This is due to the valence shell being closer to the nucleus, so there is a ___________ nuclear force of attraction.
It becomes easier for them to attract and _________ electrons. So the smaller the atom, the easier it is to attract _____________ and the more reactive the non-metal will be.
metals
reactive
metals
stronger
gain
electrons

28. Ionization Energies

29. Electronegativity
Electronegativity is a measure of the _________________ of an atom for the electrons in a chemical bond
- The higher the electronegativity of an atom, the greater its attraction for bonding electrons
Elements with low ionization energies have low electronegativities because their nuclei do not exert a strong attractive force on _____________
attraction
electrons

30. Electronegativities of the representative elements

31. Ionic Radii (Cations)
What trends do you observe through studying this chart?

32. Ionic Radii (Anions)
What trends do you observe through studying this chart?

33. Ionic Radii
What similarities did you identify by observing the last two slides?
_________________________ _________________________ _________________________ _________________________ _________________________
What differences did you identify
by observing the last two slides?
_________________________ _________________________ _________________________ _________________________ _________________________

34. Selected data on the Group 1 Alkali Metals
Group 1A Trend Data
Selected data on the Group 1 Alkali Metals
Chemical symbol, name
Atomic number
Electron arrangement
melting point
boiling point
Density g/cm3
atomic radius pm
Li, lithium 3
2.1
181oC , 454K
1347oC, 1620K
0.53
152
Na, sodium 11
2.8.1
98oC, 371K
883oC, 1156K
0.97
186
K, potassium 19
64oC, 337K
774oC, 1047K
0.86
231
Rb, rubidium 37
39oC, 312K
688oC, 961K
1.48
244
Cs, cesium 55
29oC, 302K
679oC, 952K
1.87
262
Fr, francium 87
27oC, 300K
677oC, 950K
approx. 2
270

35. Valence electrons and ions
Outer electrons determine the _______________ properties of an atom
Octet rule
Atoms attempt to acquire a full valence energy level of ____ electrons, like __________________
The exception is _________, which has only __ electrons
This is why atoms form ____________ ________
Electrons can be _____________, _________, or _______________ in the process
Example: sodium (Na)
chemical 8
the noble gases
Helium 2
chemical
bonds
gained
lost
shared

37. Ion Formation and the Periodic Table
Elements in a group have the same number of _____________________
The number of ___________________ can be found by looking at the _______________
Group 1 = ___ valence electron
Group 2 = ___ valence electrons
Group 13 = ___ valence electrons
Group 15 = ___ valence electrons
Group 16 = ___ valence electrons
Group 17 = ___ valence electrons
valence electrons
valence electrons
group number 1 2 3 5 6 7

38. Ion Formation and the Periodic Table
The charge of the ion formed by the elements within a _________ can also be predicted
Example: the elements in Group 2 have ____ valence electrons, so they will __________ electrons to get a full valence energy level.
Group 1 – lose 1 electron – form _____ ions
Group 2 – lose 2 electrons – form _____ ions
Group 13 – lose 3 electrons – form ______ ions
Group 15 – gain 3 electrons – form ______ ions
Group 16 – gain 2 electrons – form ______ ions
Group 17 – gain 1 electron – form ______ ions
group 2
lose 2 +1 +2 +3 -3 -2 -1

39. Formation of Ions Na+ Na 11 protons 11 protons 11 electrons

40. Formation of Ions Cl- Cl 17 protons 17 protons 18 electrons

41. Electron Dot Diagrams
Since we are usually only interested in the behavior of the ___________ electrons, we will occasionally omit the interior electrons from our diagrams.
valence Na

42. Electron Dot Diagrams
For atoms with multiple electrons, we follow these guidelines:
Imagine that there is a square around the element’s symbol. Place one electron on each side of the square before adding a second electron to any side. O

43. We will use these diagrams to help us later on when we study chemical bonding.
Note that only the main group or representative elements are shown.
We do not draw the transition metals using this method.