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Revision ScienceMid term

Thursday 13 April 2023

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Q1: What is respiration?Ans:

The process in living organisms of taking in oxygen from the surroundings and giving out carbon dioxide (external respiration). During which energy is released and carbon dioxide produced (internal respiration).

Equation of RespirationGlucose + Oxygen Carbon dioxide + water + Energy

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The Respiratory System includes the nose, mouth, trachea, bronchi, diaphragm, and lungs.

1.Carbon monoxide gas starves the body of oxygen.

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The lung on left side of our body is a bit smaller than the lung on the right.This extra space on the left leaves room for your heart.

Why do we Yawn?Why do we Sneeze?What cause Hiccups??

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Every thing is made up of matter.

Atoms combined to form a molecule.

All matters are made up of elements.Element are made up of molecules.

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There are 92 elements that occur naturally.

Electrons revolves in shells.

Atoms are made of a nucleus that contain protons and neutrons.Electrons orbit the nucleus.

There are mainly 4 shells namely K,L,M,NAn atom have same number of proton and electron. It is also called atomic number.

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Proton have a positive (+) charge.Electron have a negative (-) charge.Neutron have No charge.

Atomic Structure

The structure of the atom

ELECTRON – negative, mass nearly nothing

PROTON – positive, same

mass as neutron (“1”)

NEUTRON – neutral, same

mass as proton (“1”)

The Ancient Greeks used to believe that everything was made up of very small particles. I did some experiments in 1808

that proved this and called these particles ATOMS:

Dalton

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The Atom

Nucleus Electron

Shell or Orbit

The Atom Hydrogen

Proton Electron

Hydrogen has one proton, one electron and NO neutrons

The Atom Helium

ElectronProton

Neutron

Helium has two electrons, two protons and two neutrons

Mass and atomic numberParticle Relative Mass Relative Charge

Proton 1 1

Neutron 1 0

Electron 0 -1

MASS NUMBER = number of protons + number of neutrons

SYMBOL

PROTON NUMBER = number of protons (obviously)

The Atom Helium

ElectronProton

Neutron

Helium has two electrons, two protons and two neutrons

The Atom Lithium

Protons

Neutrons

Electrons

The Atom Beryllium

Protons

Neutrons

Electrons

Beryllium has four electrons, four protons and five neutrons.

The Atom Boron

Protons

Neutrons

Electrons

Boron has five electrons, five protons and six neutrons.

The Atom Carbon

Protons

Neutrons

Electrons

Carbon has six electrons, six protons and six neutrons.

The Atom Nitrogen

Protons

Neutrons

Electrons

Nitrogen has seven electrons, seven protons and seven neutrons.

The Atom Oxygen

Protons

Neutrons

Electrons

Oxygen has eight electrons, eight protons and eight neutrons.

The Atom Fluorine

Protons

Neutrons

Electrons

Fluorine has nine electrons, nine protons and ten neutrons.

The Atom Neon

Protons

Neutrons

Electrons

Neon has ten electrons, ten protons and ten neutrons.

The Atom Sodium

Protons

Neutrons

Electrons

Sodium has eleven electrons, eleven protons and twelve neutrons.

How many protons, neutrons and electrons?

Mendeleev

Periodic tableThe periodic table arranges all the elements in groups according to their properties.

Horizontal rows are called PERIODS

Vertical columns are called GROUPS

How shells fill

• The first electron shell can only hold a maximum of two electrons.• The second electron shell can hold a maximum of eight electrons.• The third electron shell can also hold a maximum of eight electrons.• The fourth electron shell can also hold eight electrons.

H He

Li Be B C N O F Ne

NaMg Al Si P S Cl Ar

K Ca Fe NiCu Zn Br Kr

Ag I Xe

PtAu

Hg

The Periodic TableFact 3: Most of the elements are metals:

These elements are metals

This line divides metals from non-metals

These elements are non-metals

Group 1 – The alkali metals

Li

Na

K

Rb

Cs

Fr

Group 0 – The Noble gases

He

Ne

Ar

Kr

Xe

Rn

Group 7 – The halogens

F

Cl

Br

I

At

The halogens – some reactions1) Halogen + metal:

Na

+

Cl

-

Na Cl+

2) Halogen + non-metal:

H Cl+ Cl H

Halogen + metal ionic salt

Halogen + non-metal covalent molecule

How shells fill

• The first electron shell can only hold a maximum of two electrons.• The second electron shell can hold a maximum of eight electrons.• The third electron shell can also hold a maximum of eight electrons.• The fourth electron shell can also hold eight electrons.

Electron structureConsider an atom of Potassium:

Potassium has 19 electrons. These are arranged in shells…

Nucleus

The inner shell has __ electrons

The next shell has __ electrons

The next shell has __ electrons

The next shell has the remaining __ electron

Electron structure

= 2,8,8,1

How the shells fill with electrons

Element Shell 1 Shell 2 Shell 3 Shell 4

HydrogenH

1 electron 0 electron 0 electron 0 electron

HeliumHe

2 electron 0 electron 0 electron 0 electron

How the shells fill with electrons

Element Shell 1 Shell 2 Shell 3 Shell 4

LithiumLi

2 electron 1 electron 0 electron 0 electron

BerylliumBe

2 electron 2 electron 0 electron 0 electron

How the shells fill with electrons

Element Shell 1 Shell 2 Shell 3 Shell 4

BoronB

2 electron 3 electron 0 electron 0 electron

CarbonC

2 electron 4 electron 0 electron 0 electron

How the shells fill with electrons

Element Shell 1 Shell 2 Shell 3 Shell 4

NitrogenN

2 electron 5 electron 0 electron 0 electron

OxygenO

2 electron 6 electron 0 electron 0 electron

How the shells fill with electrons

Element Shell 1 Shell 2 Shell 3 Shell 4

FluorineF

2 electron 7 electron 0 electron 0 electron

NeonNe

2 electron 8 electron 0 electron 0 electron

How the shells fill with electrons

Element Shell 1 Shell 2 Shell 3 Shell 4

SodiumNa

2 electron 8 electron 1 electron 0 electron

MagnesiumMg

2 electron 8 electron 2 electron 0 electron

How the shells fill with electrons

Element Shell 1 Shell 2 Shell 3 Shell 4

AluminiumAl

2 electron 8 electron 3 electron 0 electron

SiliconSi

2 electron 8 electron 4 electron 0 electron

How the shells fill with electrons

Element Shell 1 Shell 2 Shell 3 Shell 4

PhosphorusP

2 electron 8 electron 5 electron 0 electron

SulphurS

2 electron 8 electron 6 electron 0 electron

How the shells fill with electrons

Element Shell 1 Shell 2 Shell 3 Shell 4

ChlorineCl

2 electron 8 electron 7 electron 0 electron

ArgonAr

2 electron 8 electron 8 electron 0 electron

How the shells fill with electrons

Element Shell 1 Shell 2 Shell 3 Shell 4

Potassium 2 electron 8 electron 8 electron 1 electron

CalciumCa

2 electron 8 electron 8 electron 2 electron

The First Twenty Elements

• Hydrogen 1,0,0,0• Helium 2,0,0,0• Lithium 2,1,0,0• Beryllium 2,2,0,0• Boron 2,3,0,0• Carbon 2,4,0,0• Nitrogen 2,5,0,0

First 20 Elements continued

• Oxygen 2,6,0,0• Fluorine 2,7,0,0• Neon 2,8,0,0• Sodium 2,8,1,0• Magnesium 2,8,2,0• Aluminium 2,8,3,0• Silicon 2,8,4,0

First 20 Elements continued

• Phosphorus 2,8,5,0• Sulphur 2,8,6,0• Chlorine 2,8,7,0• Argon 2,8,8,0• Potassium 2,8,8,1• Calcium 2,8,8,2

Reactions

• Sodium and Chlorine react to form • Sodium Chloride.• Iron and Chlorine react to form • Iron Chloride.• 2Na + Cl2 2NaCl.• Fe + Cl2 FeCl2.

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mixture and compound???

Average vs. Instantaneous speed

• Average speed is the distance traveled divided by the time to travel.

• Instantaneous speed is the average speed for infinitely small distances and times.

TimeTravel

TotalSpeedAverage

Covered Distance

0)(~ Amount Time Minimal In

Covered DistanceSpeed ousInstantene

“Conversion”

• Convert the Scale:

• 46 sec = =0.76 min = =0.0127 hrs

• 37 sec = =0. 01027 hrs = =0. 616 min

• 29 min =29 x 60 = 1740 sec= =0.483 hrs

“Molecular masses”

• Calculate molecular masses of the following:

• H2SO4 = (1x2) + 32 + (16x4)=2+32+64=98

• CaCO3 = 40+ 12 + (16x3)=40+12+48=100

• NaCl= 23 + 35.5=58.5

• H2O = (1x2) + 16=188

• CO2= 12+ (16x2)=12+32=44

• NaNO3= 23+14 + (16x3)= 23+14+48=85