Quarter 3

Notes

Matter Anything that occupies space and has mass. It is made up of particles.
Example : wood, water, balloon

Properties - characteristics that describe a sample of matter

1. Mass- the amount of matter the object has.
2. Volume- the space occupied by an object
History Leucippus Democritus - ‘ ATOMOS’ ( indivisible and indestructible)
Of matter Aristotle- challenged Leucippus and Democritus
John Dalton – ATOM (the smallest particle of an element that has all the
properties of
the element )

molecule - two or more atoms combined together in a specific arrangement.

Example - H2O ( water ) 2 Hydrogen atoms and 1 Oxygen atom.

Atoms are too small to observe. These particles cannot be seen under the high-
powered light microscopes used in school laboratories. The size of an atom is
measured in angstroms. One angstrom is a unit of length equal to one ten
millionth of a millimetre.

scanning tunneling microscope (STM) - allows scientists to view and scan the
surface of very small particles like atoms

Pointillism - is a method of painting using dots to come up with various effects.

The dots are placed singly, in rows, or randomly.

STATES three forms of matte ( SOLID, LIQUID, AND GAS)

OF SOLID
MATTER -has both a definite shape and a definite volume:
It is rigid.
-compressed to any appreciable extent.
-molecules (held tightly together, usually in definite arrangements, )in which the
molecules can wiggle only slightly in their otherwise fixed positions.

LIQUID
A liquid has a distinct volume independent of its container but has no specific
shape: It assumes the shape of the portion of the container that it occupies
the molecules are packed more closely together, but still move rapidly, allowing
them to slide over each other; thus, liquids pour easily

GAS
(also known as vapor) has no fixed volume or shape; rather, it conforms to the
volume and shape of its container. A gas can be compressed to occupy a
smaller volume, or it can expand to occupy a larger one. In a gas the molecules
are far apart and are moving at high speeds, colliding repeatedly with each other
 and with the walls of the container

PHASES 1. MELTING - When ice cubes are placed in a glass of water, it melts. Why? It is
OF because water has a higher temperature than the ice. Heat energy flows from
MATTER the water to the ice. Heat transfer transpires from an object with a higher
temperature to an object with a lower temperature. The heat absorbed by the ice
is used to break the hydrogen bonds holding the water molecules together in the
ice crystals. When molecules are removed, the ice cubes shrink. The process
continues until all of the ice melts.
2. VAPORIZATION (evaporation) -Once the ice has melted, additional energy
added to the system increases the kinetic energy of the liquid molecules.
Particles that escape the liquid enter the gas phase. For the substance that is
ordinarily a liquid at room temperature, the gas phase is called gas or vapor.
Vaporization is the process by which a liquid changes to gas or vapor. When
vaporization occurs only on the surface of a liquid the process is called
evaporation.
3. SUBLIMATION- Solid iodine and solid carbon dioxide (dry ice) change
directly from solid phase to gas phase. The process is called sublimation.
Mothballs, which contain the compound naphthalene sublimates. Have you
noticed that ice cubes left in the freezer for a long time shrink? It is because they
undergo the process of sublimation.
4. CONDENSATION -Condensation of water vapor all involves the transfer of
energy. A vapor molecule that comes in contact with the surface of a cold glass
window transfers its heat to the cold glass. The water vapor that condenses on
the leaves of the grass forms liquid droplets called dew. Clouds are made
entirely of water droplets. When the drops increase in size, they become heavy,
and fall to the ground as rain.
5. FREEZING- You place an ice cubes maker filled with water in the freezer. As
heat is removed from the water, the molecules lose kinetic energy, the velocity
of the molecules decreases. When enough energy has been removed, the
hydrogen bonds between water molecules keep the molecules fixed or frozen
into set positions. Freezing is the reverse of melting.
6. DEPOSITION -When water vapor comes in contact with the cold window
 glass in winter, it forms a solid deposit on the window glass called frost.
Deposition is the process by which a substance changes from a gas or vapor to
a solid state without first changing into a liquid state. Deposition is the reverse of
sublimation. When water vapor high up in the air changes directly into ice
crystals, you get a snowflake. Energy is released as the crystal forms.

Phase Changes- changes into a solid, a liquid, or a gas

Sub- - components of the atom

atomic Sub-atomic Particles
Particles 1.protons
2. electrons
3.neutrons

History of Dalton’s Atomic Theory ( SOLID SPHERE MODEL)

Atom The idea of the atom was not furhter explored until a little over two centuries ago
when John Dalton (1766 – 1844) presented concrete evidence that all matter is
made of very small particles called atoms. An atom is the smallest particle of an
element that has all properties of the element. Although two century old,
Dalton’s atomic theory remains valid in modern chemical thought.
1. Elements are made of extremely small particles called atoms.
2. Atoms of a given element are identical in size, mass, and other properties;
atoms of different elements differ in size, mass, and other properties.
3. Compounds are made by a combination of two or more different kinds of
atoms.
4. A chemical reaction is a rearrangement of atoms.
5. Atoms cannot be subdivided, created, or destroyed.

J. J. Thomson (1856-1940)
• Proved that atom can be divided into smaller parts.
• The next major advance in the history of the atom was the discovery of
electrons in 1897. Electrons have negative charged and the first subatomic
particles to be identified.
• In 1897, proposed the Plum Pudding Model which states that atoms mostly
consist of positively charged material with negatively charged particles
(electrons) located throughout the positive material.

Earnest Rutherford (1871-1937)

• A physicist from New Zealand named Ernest Rutherford made the next major
discovery about atoms. He discovered the nucleus (center of atom). He later
discovered protons that has positively charged particle. Rutherford thought that
electrons randomly orbit the nucleus
• In 1909, he performed the Gold Foil Experiment and suggested the following
characteristics of the atom:
1. An atom consists of a small core, or nucleus, that contains most of the mass.
2. This nucleus is made up of particles called protons, which have a positive
charge
3. The protons are surrounded by negatively charged electrons, but most of the
atom is actually, empty space o Rutherford’s model was called the “planetary
model”
• Because of Rutherford’s gold experiment, the plum pudding model was
replaced by the nuclear model of the atom. He was also referred to as “Father of
Nuclear Physics”.
James Chadwick (1891-1974)
• Chadwick discovered a third type of subatomic particle, which he named the
neutron.
• Neutrons always reside in the nucleus of atoms and they are about the same
size as protons. Neutrons do not have any electrical charge; they are electrically
neutral

Neils Bohr (1885-1962)

• Neils Bohr used math to show electrons were found in shells at specific
distances from the nucleus. This explained observations from experiments.
• In 1913, proposed the Bohr Model, which suggests that:
1. Electrons travel around the nucleus of an atom in orbits or definite paths.
2. Electrons can jump from a path in one level to a path in another level
(depending on their energy) electrons can jump.

Erwin Schrodinger (1887-1961)

• In 1926, he further explained the nature of electrons in an atom by stating that:
-the exact location of an electron cannot be stated; therefore, it is more accurate
to view the electrons in regions called electron clouds; electron clouds are
places where the electrons are likely
to be found
Calculations Neutron = Atomic Mass – Atomic Number
-proton Proton = Atomic Number
-electron Electron = if the ion is POSITIVE, subtract the number of ions (Z 2+) with
-neutron the given number of protons.
-charges = if the ion is NEGATIVE, add the number of ions (Z 2- ) with
-atomic the given number of protons.
mass Atomic Mass = Atomic Number + Neutron
-atomic
number

History of Johann Dobereiner, -a German chemist who formed the triads of elements with
the similar properties like the triad of calcium, barium and strontium.
periodic
table John Newlands, an English chemist proposed the Law of Octaves. He based
his classification of elements on the fact that similar properties could be noted
for every eight element when they are arranged in order of increasing atomic
masses. Around 1869 two scientists determined a way to put the elements in
order.
Lothar Meyer and Dmitri Mendeleev both came up with periodic tables that
showed how elements should be grouped. It is interesting to note that these two
scientists did not personally know each other, yet they came up with the same
conclusions. Both scientists were teachers living and working in different places.
Meyer lived and worked in Germany while Mendeleev in Russia. Both arranged
the elements in order of increasing atomic mass while putting in groups those
with similar properties. Both of them also left blank spaces in their tables,
believing that these spaces would be filled later with elements yet to be
discovered.
Henry Moseley, an English physicist observed that the order of the X-ray
frequencies emitted by elements follows the ordering of the elements by atomic
number. This observation led to the development of the modern periodic law
which states that the properties of elements vary periodically with atomic
number. The atomic number is equal to the number of protons in the nucleus of
an atom. The atomic number is a common characteristic of all atoms of an
element. The modern periodic table is arranged by atomic number

Periodic
Table

The modern periodic table organizes elements in such a way that information
about the elements and their compounds are easily revealed.
 The vertical columns of the periodic table, called groups, identify the principal
families of elements.

Some families have their special names. Refer to the figure on the right,
Group 1 -alkali metals ( Magnesium – most reactive metal)
Group 2 -alkaline earth metals

Metalloids- exhibit properties of both metals and nonmetals

Metals - Elements that are shiny, malleable, and good conductors
of heat and electricity
Group 17 - halogens
Group 18 -noble gases ( Helium, Neon, Argon, Krypton, Xenon,
Radon, Ununoctium )
- Complete valence electron shells
- In the gaseous state it form diatomic covalent molecules
Groups 13 to 16 are named based on the first element found in their families.
Group 16 -the Oxygen Group.
Period -The horizontal rows or periods are numbered from the top to bottom.
For example, the elements lithium (Li) across neon (Ne) form Period 2.There are
7 horizontal rows or periods in the periodic table. The elements are grouped into
blocks or series in the periodic table. In the later grades, you will learn how
elements were grouped in blocks. Refer to the figure above, Group 3 to Group
12 constitutes one block wherein elements in this block are referred as the
transition elements.
Lanthanides and actinides are special series of elements but are also part of
the transition block; they are also called the inner transition elements. Elements
from the taller columns (groups 1, 2, and 13 213 through 18) are called the
representative elements or main groups of the periodic table. This arrangement
allows us to study systematically the way properties vary with the element’s
position in the table. Similarities and differences among the elements are easier
to understand and remember.

Trivia:
Mercury - not solid at room temperature
Chlorine -the highest electron affinity

Electronic How do you write an electronic configuration?

Configuratio 1. Determine how many electrons are in the atom.
n 2. Arrange the energy sublevels according to increasing energy.
3. Fill each sublevel with electrons until you have used all the electrons in the
atom.
4. The sum of the superscripts equals the atomic number.