Lecture 1 Flashcards
(25 cards)
Matter
Substance of which all physical objects are made
Anything that occupies space and mass (considered weight) Solid, Liquid and Gas
Composed of atoms
If matter is separated it is
mixture
Types of mixtures
Two general classes of mixtures – heterogeneous and homogeneous
Heterogeneous mixture – the components are unevenly distributed throughout the mixture
Example: A mixture of rocks and sand
Homogeneous mixture – the components are evenly distributed throughout the mixture
A homogeneous mixture is also known as a solution
If matter is not separated it is
a pure substance
if the pure substance can and cannot be chemically decomposed
if it can its a compound
If it cant its an element
If the element does and doesnt conduct electricity
yes- Metal or graphite
no - non metal
What is a pure substance
Have uniform or same chemical composition throughout . Two kinds of pure substances elements and compounds
What is an Element
Substance that cant be broken down into simpler substances even by chemical reactions. Separated into metal and non metals
What is a compound
A substance composed of two or more elements
Metal different from non metals
Difference between metal and non metal can be distinguished by luster . Non metals are dull except for carbon as diamond. Elements that are gases at room temperature are also non metals
Atom and examples
The smallest intact component of all matter
The basic unit of an element that enters into a chemical combination
A chemical element is a pure chemical substance consisting of one type of atom
Cannot be broken down into any simpler form of matter
Example H, C , O Fe
3 main particles and charge
Protons - positively charged (+)
Neutrons - no charge
Electrons - negatively charged (-)
What is nucleas
centre of an atom Nucleus contain it is positively charged Protons (+) and neutrons (no charge)
Electrons are outside the nucleus
What is atomic number
Number of protons in the nucleus of an atom (Positive charge)
The identity of an element is determined by its atomic number
Each element has a unique atomic number
Number of protons (+) = Number of electrons
(Atomic Number = number of electrons)
What is mass number
Total number of Protons + Neutrons in the nucleus (P + N)
Atomic number + number of neutrons
Number of neutrons = difference between the mass number and atomic number
What are Isotopes and the examples
Atoms that have the same Atomic Number but different Mass Number
Atoms with the same number of Protons, but different number of Neutrons
Example: Hydrogen , Deuterium, Tritium
Electron Energy Levels
An Electron’s Energy Level is the amount of energy required by an electron to stay in orbit
Shells and subshells are the orbits of the electrons in an atom E1-E4
Each shell can hold a maximum number of electrons
How to determine maximum number of electrons in a shell
X = 2n2
X is the maximum number of electrons in energy number n
n represents energy level / shell number
How are elements arranged on the periodic table
Elements are arranged in order of increasing atomic number from left to right
Elements are arranged horizontally in rows called periods
The vertical columns are called groups/families
Elements in the same column have similar physical and chemical properties
Main group elements – elements in the first two and last six columns (1A – 8A)
The middle section (column) is known as - transition metal elements
Metals, nonmetals, metalloid and gases
What are Metal
elements that are good conductor of both electricity and heat
Exist as solids at room temperature (except mercury)
Form cations and ionic bonds with non- metals
Many metals serve as important macronutrients –micronutrients - minerals in the body
What are macronutrients
protein carbs, fats Sodium (Na), Potassium (K), Magnesium (Mg), Calcium (Ca), Chloride (Cl)
What are micronutrients
minerals in the body Iron (Fe), Cobalt (Co), Copper (Cu), Zinc (Zn), Fluoride (F)
Non-metals:
Poor conductors of heat and electricity when compared to metals
Exist as solids, liquids and gases at room temperature
They form acidic oxides (whereas metals generally form basic oxides)
Hydrogen is classified as a nonmetal
Nonmetals make up the important molecular compound in the body (building blocks) H, C, O N,
Metalloids
Have properties of both metals and nonmetals
Metalloids often behave as semiconductors
Can carry an electric charge under special conditions
This property makes metalloids useful in computers and calculators
