Chemistry 101 - chapter 1 - Atoms and isotopes

What are the 3 states of matter and what about their shape and vlome

Solids: relatively rigid and have fixed shapes and volumes

Liquids: -fixed volumes but flow to assume the shape of their container

Gases: neither fixed shapes nor fixed volum

A pure chemical substance is?

And give me an example

It is any matter that has a fixed chemical composition and characteristics properties

Example it is oxygen and it is odorless ,colorless

What are the Types of Pure Substance?

And examples

There are two types

1- element : a substance that cannot be broken down into simpler particles

Ex : sodium

2- compounds:contains two or more elements bonded chemically

Ex : sodium chloride (table salt)

فصل لي ال matter وانواعه مع التعاريف

What is the physical property

physical properties: are characteristics that can be observed without changing the composition of sample

Example for physical property

Mass , colour , volume

What is the chemical properties?

describe the characteristic ability of a substance to react to form new substances

Example for chemical properties?

flammability and corrosion

What is the physical change?

are changes in which no bonds are broken or formed and Chemical composition of matter does not change

Ex for physical change

1-Changes of state (changes from a solid to a liquid or a gas and vice Versa)

2-Separation of a mixture

3-Physical deformation (cutting, denting, stretching)

4-Making solutions (special kinds of mixtures)

What is the chemical change?

occur when bonds are broken and/or formed Between molecules and atoms

Ex for chemical change?

Burning a candle

Rusting or Iron

Baking a cake

Electrolysis of water

What is the definition of density?

Density is defined as mass per unit volume

Density depends on

1- temperature

2- pressure

Density determines in lab by :

1-Dimensional method

2- Displacement method

determine the density of an unknow metal cube

that has side length 3.00 cm and mass is 310.672g

راجع ال significant figures بالكتاب

Nothing

What is the metric system

Metric prefixes –are other units related to the base unit by power of 10.

What is postulates of Dalton’s atomic theory ?

1-An atom is the smallest unit of an element that can participate in a chemical change

2-an element consists of only type of atom, which has a mass that is characteristic of the element and is the same for all atoms of that element.

3. Atoms of one element differ in properties from atoms of all other elements.

4. A compound consists of atoms of two or more elements combined in a small, whole-number ratio. In a given compound, the numbers of atoms of each of its elements are always present in the same ratio.

5-Atoms are neither created nor destroyed during a chemical change

Modern atomic theory?

شكل الذرة وانها تحتوى p و n وحولها الكترونات

والقطر من النواة الى حدود الذرة 10 اوس -10

والقطر للنواة 10 اوس -15

What is the Atomic number and mass number? And what their symbols?

1. Atomic number (Z):is the number of protons in the nucleus of an atom

“Atomic number determines the identity of the atom”

Mass number(A)–is the of total number of protons and neutrons in an

A-Z =

No.Neutrons

Atoms are electrically neutral if

Atoms are electrically neutral if they contain the same number of positively charged protons and negatively charged electrons.

When Atom called an ion ?

When the numbers of protons and electrons is not equal, the atom is

electrically charged and is called an ion.

What is the rule of chemical symbol?

Only the first letter of a symbol is capitalize

example: Co is symbol for element Cobalt

---

However, CO is compound carbon monoxide which has element Carbon and Oxygen in it

The symbol for an atom indicates the element via its usual two -letter

symbol, the mass number as a left superscript, the atomic number as a

left subscript (sometimes omitted), and the charge as a right superscript is called ?

Isotopes are :

are nuclides having the same atomic number but different mass numbers

“Most elements occur in nature as mixtures of isotopes”

hydrogen are especially important

They have names and symbols

What is the isotopes effect?

when different isotopes exhibit different chemical behavior ,more common in lighter elements