Atom, Matter & Organic.pptx

Introduction to Chemistry

Atom, Molecule & IonsMatter and Study of Change

Organic Chemistry

Lecture-2

Introduction to Chemistry 2

Chemistry is the study of matter and the interactions between different types of matter and energy. The fundamental building block of all matter is the atom. An atom consists of three main parts: protons, neutrons, and electrons.

Atom

1/11/2015


Atom (contd.)

The center of an atom is called nucleus that contain neutrons and protons.

The nucleus is surrounded by moving electrons.

Protons have a positive electrical charge. Neutrons have no electrical charge. Electrons have a negative electrical charge.

Chemical reactions involve interactions between the electrons of one atom and the electrons of another atom.

1/11/2015


Atoms which have different amounts of electrons and protons have a positive or negative electrical charge and are called ions.

Ion

1/11/2015


Example 1: Identify the number of protons and electrons in the Mg+2 ion.

Solution: The atomic number of Mg

(magnesium) is 12, which means that magnesium has 12 protons. While a neutral atom for magnesium would have the same number of electrons as protons, the ion is shown to have a +2 charge. This means it has 2 fewer electrons than the neutral atom or 12 - 2 = 10 electrons.

Answer: 12 protons, 10 electrons

Protons & Electrons in Ions

1/11/2015


Example 2: Give the symbol of an ion which has 10 e- and 8 p+.

Solution: The notation e- refers to electrons; p+ refers to

protons. Since the number of protons is an element's atomic number, the element with an atomic number of 8 is oxygen, which has the symbol O. The problem states that there are more electrons than protons, so we know the ion has a negative net charge. Determine the net charge by looking at the difference in the number of protons and electrons: 10 - 8 = 2 more electrons than protons, or a -2 charge.

Answer: O-2

1/11/2015


When two or more atoms are bonded together, they make larger building blocks of matter called molecules.

A molecule is the smallest unit of a compound that shows the properties of that compound.

It may contain two atoms of the same element, such as N2, O2 and H2, or they may consist of two or more different atoms, such as NaCl, HCl, H2SO4, C6H12O6, CH4 and H2O.

Molecule

1/11/2015

Introduction to Chemistry 81/11/2015


There are many kinds of atoms called elements. Elements differ from one another by the number

of protons and electrons they contain. The number of protons of each atom of an

element is called its atomic number. The mass of the nucleus i.e. protons and neutrons

of the atom of an element is known its atomic mass.

Elements, Atomic Number and Atomic Mass

1/11/2015


Atoms of an element that have the same atomic number but differ in their atomic mass are called isotopes.

The nuclear symbol indicates the composition of the nucleus.

Isotopes and Nuclear Symbols

1

111H

11

1121H H

13

hydrogen deuterium tritium

mass number

atomic number

1/11/2015


It is a form of water that contains deuterium (an isotope of hydrogen) a larger than normal amount of the hydrogen that is available in normal water.

It has a density about 11% greater than water, but otherwise, is physically and chemically similar.

Applications: For spectroscopic analysis e.g. NMR, FTS etc.

Heavy Water, D2O

1/11/2015


Example 3: Write the nuclear symbols for three isotopes of oxygen in which there are 8, 9, and 10 neutrons, respectively.

Solution: The element symbol for oxygen is O and its atomic number is 8. The mass numbers for oxygen must be 8 + 8 = 16; 8 + 9 = 17; 8 + 10 = 18. The nuclear symbols are written this way:

168O, 17

8O, 188O

Example 4: Write the nuclear symbol for an atom with 32 protons and 38 neutrons.

Solution: The element with 32 protons is germanium, which has the symbol Ge. The mass number is 32 + 38 = 70, so the nuclear symbol is: 70

32Ge

Problems

1/11/2015


Earth’s interior can be divided into- crust, mantle and core.

Earth’s crust extends from the surface to a depth of about 40 km.

Scientists have been able only to study the crust.

Distribution of elements on Earth and in Living Systems

Core

MantleCrust(40 km) (2900 km)

(3480 km)

Figure. A cross-section of the Earth

1/11/2015


The majority of elements are naturally occuring. Of the 83 elements that are found in nature, 12

make up 99.7% of Earth’s crust by mass. They are (in decreasing order of natural abundance)

oxygen (O), silicon (Si), aluminum (Al), iron (Fe), calcium (Ca). magnesium (Mg), sodium (Na), potassium (K), titanium (Ti), hydrogen (H), phosphorus (P), and manganese (Mn).

Core consisting mostly of iron at the centre of Earth. Surrounding the core is a layer called mantle, which consists of hot fluid containing iron, carbon, silicon, and sulfur.

Elements on Earth

1/11/2015


The essential trace elements in the human body which make up about 0.1 % of body mass are iron (Fe), copper (Cu), zinc (Zn), iodine (I), and cobalt (Co).

These elements are necessary for biological functions such as growth, transport of oxygen for metabolism, and defense against disease.

Too much or too little of these elements in our body over an extended period of time can lead to serious illness, retardation, or even death.

Elements in Human Body

1/11/2015


Abundance of ElementsNatural Abundance of the

Elements

ElementPercent by Mass(g/100g of sample)

Oxygen 45.5Silicon 27.2Aluminum 8.3Iron 6.2Calcium 4.7Magnesium 2.8All others 5.3

Abundance of the Elements in the Human Body

ElementPercent by Mass(g/100g of sample)

Oxygen 65Carbon 18Hydrogen 10Nitrogen 3Calcium 1.6Phosphorus 1.2All others 1.2

1/11/2015


Q-1: To change Li to Li+, you need to: (a) add one electron

(b) remove one proton (c) remove one electron (d) add one neutron

Q-2: Fe2+ and Fe3+ are different: (a) ions

(b) isotopes (c) elements (d) atoms

Q-3: 14

6C and 126C are examples of carbon:

(a) ions (b) neutrons (c) isotopes (d) molecules

Quizzes

1/11/2015


Q-4: 146C has how many protons?

(a) 6 (b) 12 (c) 14 (d) 20

Q-5: Li+ and Cu2+ are examples of: (a) anions

(b) cations (c) isotopes (d) molecules

Q-6: What is the symbol for an ion which has 8 protons and 10

electrons? (a) N3-

(b) O2-

(c) O3-

(d) F-

1/11/2015


Q-7: What is the nuclear symbol for the isotope of oxygen which has 9 neutrons? (a) 16

8O (b) 17

8O (c) 18

8O (d) 18

9O Q-8: Li+ has how many electrons? (hint: the atomic number of lithium is 3) (a) 0

(b) 1 (c) 2 (d) 3

Q-9: How many protons, neutrons, and electrons does 7

4Be2+ have? (a) 4,3,2

(b) 4,3,4 (c) 4,3,6 (d) 4,6,3

Q-10: N3- has: (a) 7 protons and 4 electrons

(b) 7 protons and 10 electrons (c) 7 protons and 11 electrons (d) 8 protons and 11 electrons

1/11/2015


Matter is anything that occupies space and has mass. All matter, at least in principle, can exist in three states: solid, liquid and gas.

Solids have definite volume and shape. Liquids have definite volume but no definite shape. Gases have neither definite volume nor definite shape, they will fill up whatever space they put in.

Matter

1/11/2015


The Three States of Matter

1/11/2015


A substance is matter that has a definite or constant composition and distinct properties. Examples are water, silver, ethanol, table salt, carbon dioxide etc.

Over 13 million substances are known and the list is growing rapidly.

A mixture is a combination of two or more substances in which the substances retain their distinct identities. Some examples are air, soft drinks, milk, cement etc.

Substances and Mixtures

1/11/2015


A substance can be either an element or a compound.

An element is a substance that cannot be separated into simpler substances by chemical means. Examples are hydrogen, helium, sodium, iron, silicon etc. About 113 elements have been positively identified. Eighty-three of them occur naturally on earth and scientists have created others.

A compound is a substance composed of atoms of two or more elements chemically united in fixed proportions. Examples are water, sodium chloride, silica etc.

Elements and Compounds

1/11/2015


Solution is a homogeneous mixture of at least two substances. Examples are sugar solution, saline water, carbonated water, etc.

Colloids are regarded as systems in which there are two or more phases with one distributed in the other. Milk, fog, and jelly are examples of colloids.

Suspension is a heterogeneous mixture of larger particles. These particles are visible and will settle out on standing. Examples of suspensions are: fine sand or sediments in water or tomato juice.

Solution, Colloid & Suspension

1/11/2015


Types ExampleSolute less than 50%

Solvent more than 50%

Liquid Liquid Alcohol –waterAcetic acid- water

Beervinegar

Solid Liquid Salt –waterSugar – watercalcium carbonate (CaCO3)– water

Saline solutionSugar solutionhard water

Gas Liquid CO2 – waterOxygen – water

Carbonated waterOxygenated water

Gas Gas Oxygen- nitrogen Air

Types of Solution

1/11/2015


Physical properties are readily observable, like; color, size, luster, or smell.

Chemical properties are only observable during

a chemical reaction. For example, you might not know if carbon is combustible unless you tried to burn it.

Physical & Chemical Properties

1/11/2015


Intensive Properties: Properties, which do not depend on the size of the sample involved, are called intensive properties. Some of the most common intensive properties are; density, freezing point, color, melting point, reactivity, luster, malleability, and conductivity.

Extensive Properties: Properties, those do depend on

the size of the sample involved. A large sample of carbon would take up a bigger area than a small sample of carbon, so volume is an extensive property. Some of the most common types of extensive properties are; length, volume, mass and weight.

Intensive & Extensive Properties

1/11/2015


Physical changes are those changes that do not result in the production of a new substance. Some common examples of physical changes are; melting, freezing, condensing, breaking, crushing, cutting, and bending.

Chemical changes, or chemical reactions, are changes

that result in the production of another substance. Common examples of chemical changes that you may be somewhat familiar with are; digestion, respiration, photosynthesis, burning, and decomposition.

Physical & Chemical Changes

1/11/2015


The branch of chemistry that deals with carbon containing compounds is known as organic chemistry.

Carbon containing compounds are known as organic compounds.

Few exceptions: CO, CO2, CS2, Na2CO3, NaHCO3 and KCN etc.

Carbon and hydrogen containing compounds are known as hydrocarbons.

Organic Chemistry

1/11/2015


Difference between organic and inorganic compoundsOrganic compounds Inorganic compounds

1 Low melting points 1 High melting points

2 Low boiling points 2 High boiling points

3 Low solubility in water, high solubility in non-polar solvent.

3 High solubility in water, low solubility in non-polar solvent.

4 Flammable 4 Nonflammable

5 Chemical reactions are usually slow

5 Chemical reactions are rapid

6 Exhibit covalent bonding 6 Exhibit ionic bonding

1/11/2015


Coal: It is about 80% organic compounds. Crude oil: It is a complex mixture of organic compounds. Natural gas: It is a mixture of low molecular weight

organic compounds. Wood and other plant materials: Laboratory synthesis:

Sources of Organic Compounds

1/11/2015


• As foods: Carbohydrate, fats and oils, proteins, vitamins, hormones, enzymes are organic compounds.

• As medicine: Most of the drugs- antibiotics, analgesic, hypnotics etc are organic compounds.

• As clothes: Wool, silk, cotton, linen and synthetic fibres- nylon, rayon, Dacron etc. contain organic compounds.

• As fuels: Coal, crude, oil (kerosene, petrol, diesel etc.), natural gas and wood.

• Others: Perfumes, dyes, flavors, soaps, detergents, plastics etc.

Importance of Organic Chemistry

1/11/2015


Carbohydrates: Glucose, Fructose, Sucrose etc.

Lipids- Fats, Phospholipids, Steroids etc.

Proteins- Amino acids

Nucleic acids- DNA & RNA

Vitamins-A (Retinol), B1 (Thiamine hydrochloride), B2 (Ribiflavin ), C (Ascorbic Acid ), etc.

Common Organic Molecules

1/11/2015


Common Organic Molecules (contd.)

Glucose FructoseSucrose WaterH2O

MONOSACCHARIDESDISACCHARIDE

C6H12O6 C6H12O6C12H22O11

CH2

CH

CH2 OH

OH

OH

Glycerol

A saturated fatty acid

H C C C C C C C C C C COOHH

H H H H H

HHHH

H C C C C C C C C C C COOHH

H H H H H H H H H H

HHHHHHHHH

A unsaturated fatty acid

H N C C COOH

H

H H

HCH HHAmino group

side chain

Acid group

Structure of an Amino Acid

1/11/2015


What is an atom, molecule and ion? What is called an isotope. Give suitable example. What are common elements found in nature and human body. Draw a cross-section of earth and discuss its different parts. Define element, compound, substance and mixture with

examples. What are the three states of matter? Define solution, colloid and suspension with examples. Explain physical and chemical properties with examples. Explain intensive and extensive properties with examples. Explain physical and chemical changes with examples. What are called organic compounds? State the sources and

importance of organic compounds. Give examples of common organic compounds.

Probable Questions:

1/11/2015

Documents

Atom, Matter & Organic.pptx