Nairaland Jamb Tutorial Centre {chemistry Thread} - Education (4)

Welcome, Guest: Register On Nairaland / LOGIN! / Trending / Recent / New
Stats: 3,148,004 members, 7,799,442 topics. Date: Tuesday, 16 April 2024 at 09:22 PM

Nairaland Jamb Tutorial Centre {chemistry Thread} - Education (4) - Nairaland

Nairaland Forum / Nairaland / General / Education / Nairaland Jamb Tutorial Centre {chemistry Thread} (25818 Views)

2016 NAIRALAND JAMB TUTORIAL {the Physics Thread } / Nairaland 2016 Jamb Tutorial Classroom [chemistry Thread] / Nairaland Jamb Tutorial Centre. {NJTC} (2) (3) (4)

(1) (2) (3) (4) (5) (6) (7) (8) (9) (Reply) (Go Down)

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by Shaquillle(m): 8:45am On Dec 17, 2014

adebayour26:
The whatsapp group has been created already, so we are expecting your phone numbers in d mail.

pls add me to d whatsapp group

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by Akerry(m): 11:44am On Dec 17, 2014

adebayour26:
The whatsapp group has been created already, so we are expecting your phone numbers in d mail.

add me 08070922921

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 12:16pm On Dec 17, 2014

Good afternoon everyone.
How has it been with us and our academics? It's yet another time here today on this Chemistry thread and I hope the simple topic we are gonna take will be well understood.

Thanks as you follow us....

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 12:50pm On Dec 17, 2014

ATOMIC STRUCTURE

According to Dalton's atomic theory, atoms were indestructible solid particles. However, experiments involving electrolysis indicate that certain compounds contain charged particles called IONS. The formation of ions could not be explained by Dalton's atomic theory. As a result of this and other observtions, scientists had to modify their views.

The atom is made up of three main particles— electrons, protons and neutrons with the charge: negative, positive and neutral respectively.
Rutherford's atom (a scientist) consist of a positively charged core called the nucleus, where most of the masa of the atom is contained and electrons, which move around the nucleus.

The nucleus contains the Proton and the neutron. The mass of the Proton and neutron can be said to be 1unit and 1unit respectively, while that of the electron is 1/1840 unit.

The electron was discovered by J.J Thomson in 1897 by Cathode Ray experiment. In the experiment, he also observed that :
1. Cathode rays travel in straight lines and cast shadows of opaque objects placed in their paths;
2. Cathode rays are composed of only negatively charged particles;
3. Cathode rays are capable of producing mechanical motion;
4. Cathode rays are identical in nature and in ratio of charge to mass, irrespective of the nature of the residual gas in the discharge tube or of the metals used in the electrodes.
Thomson argued that these particles were fundamental particles i.e they were present in all matter. He concluded that these particles must be the electrons proposed earlier by other scientist. Thomson measure d ratio charge/ mass which is found to be 1.76x10¹¹CKg^-1.

In 1910, R.A Milikan successfully measured the charge of the electron in his oil-drop experiment. This charge is -1.6x10^-19 C. Using the above values, the mass of an electron is found to be only 9.1x10 ^-31Kg. Th mass is so small that it hardly makes any difference to the mass of the atom.

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 12:53pm On Dec 17, 2014

Be expecting more updates later in the day.

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 12:59pm On Dec 17, 2014

A Typical structure of a Carbon atom.

As we continue, we will learn that for an atom, the number of electron is the same as the number of Proton and also the same as the Atomic number.

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by Bhuumhite(f): 3:10pm On Dec 17, 2014

can u drop ur number?.. cos i can't drop my number here,i'll send a msg and u'll add me

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 6:13pm On Dec 17, 2014

Bhuumhite:
can u drop ur number?.. cos i can't drop my number here,i'll send a msg and u'll add me

send ur number into my mail: adebayour26@gmail.com

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by sammyomotola: 7:42pm On Dec 17, 2014

07033921431

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 3:25pm On Dec 18, 2014

DISCOVERY OF PROTON

Since the atom as a whole is electrically neutral, there must exist inside the atom enough positively charged components to balance the negatively charge of the electrons. Positive ions with the lightest mass were produced when the gas in the tube was Hydrogen. These positive ions (or hydrogen ions) were protons. Each proton carries a unit of positive charge. Thomson determined tge charge/mass ratio of the proton to be 9.58x10⁷Ckg^-1 which is 1840 times smaller than that of the electron. If we assume the charge on the proton to be +1, and that on the electron as -1, then the proton is 1840 times heavier than the electron.

In 1898, J.J Thomson proposed that the atom is a sphere of positively charged in which negtively charged electrons are embedded.

ATOMIC NUMBER
In 1885, Roentgen discovered that when high energy electrons in a discharge tube collide with the anode, a penetrating radiation, which he called X-rays, is produced.
In 1914, Moseley found that he could assign a number, called the atomic number to an element emits, when it is used as the anode of an X-ray tube.
N.B: The atomic number represented the number of protons in the nucleus

Discovery of Neutron
In 1932, Chadwick discovered the Neutron. The Neutron had a mass equal to that of a proton but carried no charge. The discovery of the neutron indicated that the atomic nucleus was made up of protons and neutrons.

The mass number of an atom of an element is the sum of the protons and neutrons in it.

ISOTOPY
It is phenomenon whereby atoms of a element exhibit different mass numbers but have the same atomic number. This is due to differences in the number of neutrons present in these atoms. Such atoms are known as ISOTOPES. Hence, isotopes are atoms of the same elements with the same atomic numbers but different mass number. Isotopes of an element have slightly different physical properties but exhibit the same chemical properties. This is because Neutrons contribute only to the mass of the atom, not its chemical behaviour.
E.g ³⁵₁₇ Cl and ³⁷₁₇ Cl.

Atomic number is 17, while
Mass numbers are 35 & 37 respectively.

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 3:26pm On Dec 18, 2014

More to come soonest....

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 8:31pm On Dec 18, 2014

Exercises:
Attempt the following questions
1. Differentiate between Neutralization and Esterification reaction.

2. How does the collision theory explain the rate of chemical reaction?
How does catalyst & Temperature affect the rate of chemical reaction?

3. Why is H₂SO ₄₎ not commonly used as drying agent in the preparation of Ammonia. Suggest a drying agent being used.

4. Why do atoms combine? (Chemical bonding)

5. Differentiate between Boiling and Evaporation.

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 8:38pm On Dec 18, 2014

halpher, kunlexic, preboy, bolaji3071, victar, bhuumhite, shaquillle, Dsd1pumking, fedcom, mathefaro, sorbentcrooner, come over here and check things out.

Am waiting to see who gets here first oooo.

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by Kunlexic(m): 9:34pm On Dec 18, 2014

adebayour26:

Exercises:
Attempt the following questions
1. Differentiate between Neutralization and Esterification reaction.

2. How does the collision theory explain the rate of chemical reaction?
How does catalyst & Temperature affect the rate of chemical reaction?

3. Why is H₂SO ₄₎ not commonly used as drying agent in the preparation of Ammonia. Suggest a drying agent being used.

4. Why do atoms combine? (Chemical bonding)

5. Differentiate between Boiling and Evaporation.

1.Neutraliztan is the rxn btween an acid and alkali to give salt and water while exterificatn is rxn between alkanoic acid and alkanols to form esters.
Neutralisatn is not reversible while esterrficatn is reversible
2.As the collision between particles,they acquire greater KE which is proportional to the temperature.as the temperature increases,the rate of rxn also increases.
Catalyst have no effect on the product formed,it just slows down or accelerate the rate of reactn
Increase in temperature increases the rate of reaction
3.It is not used because it reacts with ammonia to form (NH4)2SO4.the drying agent is fused CaO.
4.Atoms combine to attain the stable configuration like those of the noble gases/to achieve octet or duplet configuratn of the outermost shell like the noble gases
5.Boiling takes place at a definite temperature while evaporation taked place at all temperature.

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 10:04pm On Dec 18, 2014

Example:
An element X has two isotopes of ²⁰₁₀ X and ²²₁₀ X in the ratio of 1:3. What is the relative atomic mass of X?
Solution:
Add ratio (1:3) of occurrence together, 1+3=4
100%/4===25%

Element ²⁰₁₀ X occurred 25x1=25% in nature

²²₁₀ X occurred 25x3==75%

(20x25)/100 + (22x75)/100

===> 5 + 16.5 == 21.5

Relativ atomic mass of X is 21.5

ELECTRONIC CONFIGURATION
According to Aufbau Principle that in the building up of atoms, electron enter into orbitals in order of increasing energy. This means that electrons are fed into orbitals starting at the lowest energy level before filling higher energy levels. The Aufbau principle can be easily be derived using this:

1S 2S 2P 3S 3P 4S 3d 4P 5S 4d 5P 6S 4F 5d 6P 7S 5F 6d 7P

Note that there are four orbitals: S, P, d, F. The S-orbital is capable of occupying a maximum of 2 electrons, while the P-orbitals can take a maximum of 6 electrons, the d-orbital wil take 10 electrons while the F-orbital can occupy a maximum of 14 electrons.

In writing the electronic configuration of an element, get the atomic number, then use the format above to write the configurations following the rules strictly.
E.g: The electronic configuration of ₁₃Al.
1S² 2S ² 2P ⁶ 3S ² 3P¹
If you count the power, you will notice it's 2, 2, 6 and 3, their sum is 13 i.e it is summed up to the atomic number.

1 Like

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 11:17pm On Dec 18, 2014

Kunlexic:

1.Neutraliztan is the rxn btween an acid and alkali to give salt and water while exterificatn is rxn between alkanoic acid and alkanols to form esters.
Neutralisatn is not reversible while esterrficatn is reversible
2.As the collision between particles,they acquire greater KE which is proportional to the temperature.as the temperature increases,the rate of rxn also increases.
Catalyst have no effect on the product formed,it just slows down or accelerate the rate of reactn
Increase in temperature increases the rate of reaction
3.It is not used because it reacts with ammonia to form (NH4)2SO4.the drying agent is fused CaO.
4.Atoms combine to attain the stable configuration like those of the noble gases/to achieve octet or duplet configuratn of the outermost shell like the noble gases
5.Boiling takes place at a definite temperature while evaporation taked place at all temperature.

GBAAM, this is brilliant.

Nice one.

Be expecting more.

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by mathefaro(m): 5:04am On Dec 19, 2014

I'm always here checking things. Continue the good work

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by mathefaro(m): 5:09am On Dec 19, 2014

Kunlexic:

1.Neutraliztan is the rxn btween an acid and alkali to give salt and water while exterificatn is rxn between alkanoic acid and alkanols to form esters.
Neutralisatn is not reversible while esterrficatn is reversible
2.As the collision between particles,they acquire greater KE which is proportional to the temperature.as the temperature increases,the rate of rxn also increases.
Catalyst have no effect on the product formed,it just slows down or accelerate the rate of reactn
Increase in temperature increases the rate of reaction
3.It is not used because it reacts with ammonia to form (NH4)2SO4.the drying agent is fused CaO.
4.Atoms combine to attain the stable configuration like those of the noble gases/to achieve octet or duplet configuratn of the outermost shell like the noble gases
5.Boiling takes place at a definite temperature while evaporation taked place at all temperature.

in addition, evaporation takes place only at the surface while boiling takes place in all parts of the liquid, more so, evaporation does not really require heat or an increase in temperature to take place although an increase in temperature will increase the rate at which it occurs, but boiling on the other hand requires a specific amount of heat/temperature

1 Like

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 7:39am On Dec 19, 2014

Thank you mathefaro. We hope others' contributionsare still expected.

1 Like

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by cao(f): 8:12am On Dec 19, 2014

I see, it's that time of the year when I regret making my username as cao...

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 10:06am On Dec 19, 2014

cao:
I see, it's that time of the year when I regret making my username as cao...

lol
Calcium Oxide- CaO
Funny username.

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by dondestiny(m): 11:22am On Dec 19, 2014

08105399780

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by Nobody: 2:02pm On Dec 19, 2014

sorry guys for my absent.... I've been quite busy, bt now am back

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 2:57pm On Dec 19, 2014

Preboy:
sorry guys for my absent.... I've been quite busy, bt now am back

Welcome back.

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by Nobody: 3:39pm On Dec 19, 2014

adebayour26:

Welcome back.

glad to be back, I don't understand the electronic config part, I thought elections are configured in their successive (k,L,M,N) shells... what's the difference between that and this S,P,D,F shells

also give the electronic config of calcium

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by cao(f): 4:04pm On Dec 19, 2014

adebayour26:

lol
Calcium Oxide- CaO
Funny username.

I know what it means, but in this case they're my initials.

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by mathefaro(m): 7:34pm On Dec 19, 2014

Preboy:

glad to be back, I don't understand the electronic config part, I thought elections are configured in their successive (k,L,M,N) shells... what's the difference between that and this S,P,D,F shells

also give the electronic config of calcium

when we say electronic configurations, we mean The arrangement of the electrons(electronic) which could either be on shell shells (k,l,m,n) or on orbitals(s,p,d,f). You need to puree that there's a difference between shells and orbitals. The maximum number of atom a shell can hold is given by the formula 2n² where n is the energy level out let's say the position of the shell, as a result of that, the first shell, whose n=1, can only contain 2 electrons, subsequently, the L-shell can contain 8 electrons and so on. Therefore when writing electronic configurations, subsequent shells must be filled before going to the next shell.
Then each shell is further subdivided into orbitals and sub-orbitals which can only contain 2 electrons spinning in opposite directions. Therefore we can say shell contains orbitals on which the electrons evolve round the nucleus. S orbitals can hold 2 electrons, p orbitals can hold 6 electrons(3 sub-orbitals containing 2 electrons each), d-10 electrons(5 sub orbitals) and f-14 electrons. K shell has just one s orbital since it can contain just 2 electrons. The L shell which can hold a maximum of 8 electrons has 1 s orbital(2 electrons) and 1p orbital(6 electrons) .
So for calcium, whose atomic number ( no of protons and no of electrons) is 20, the electronic configuration in terms of:
Shell: 2,8,8,2
Orbitals: 1S²2S²2P⁶3S²3p⁶4S²
As you can see, it has 4 shells(period 4) and the valence electrons(electrons in the outermost shell) are 2(group 2)

Wow! That was such an epistle. I hope somebody would gain something from this

3 Likes 1 Share

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by adebayour26: 7:35pm On Dec 19, 2014

cao:

I know what it means, but in this case they're my initials.

Interesting....

mathefaro, Thanks for that explaination.

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by mathefaro(m): 7:46pm On Dec 19, 2014

adebayour26:

Interesting....

mathefaro, Thanks for that explaination.

my pleasure bro

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by Nobody: 8:08pm On Dec 19, 2014

mathefaro:
when we say electronic configurations, we mean The arrangement of the electrons(electronic) which could either be on shell shells (k,l,m,n) or on orbitals(s,p,d,f). You need to puree that there's a difference between shells and orbitals. The maximum number of atom a shell can hold is given by the formula 2n² where n is the energy level out let's say the position of the shell, as a result of that, the first shell, whose n=1, can only contain 2 electrons, subsequently, the L-shell can contain 8 electrons and so on. Therefore when writing electronic configurations, subsequent shells must be filled before going to the next shell.
Then each shell is further subdivided into orbitals and sub-orbitals which can only contain 2 electrons spinning in opposite directions. Therefore we can say shell contains orbitals on which the electrons evolve round the nucleus. S orbitals can hold 2 electrons, p orbitals can hold 6 electrons(3 sub-orbitals containing 2 electrons each), d-10 electrons(5 sub orbitals) and f-14 electrons. K shell has just one s orbital since it can contain just 2 electrons. The L shell which can hold a maximum of 8 electrons has 1 s orbital(2 electrons) and 1p orbital(6 electrons) .
So for calcium, whose atomic number ( no of protons and no of electrons) is 20, the electronic configuration in terms of:
Shell: 2,8,8,2
Orbitals: 1S²2S²2P⁶3S²3p⁶4S²
As you can see, it has 4 shells(period 4) and the valence electrons(electrons in the outermost shell) are 2(group 2)

Wow! That was such an epistle. I hope somebody would gain something from this

you're golden bro, everything sank it like Titanic... really grateful

1 Like

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by mathefaro(m): 9:02pm On Dec 19, 2014

Preboy:

you're golden bro, everything sank it like Titanic... really grateful

glad I could be of help

Re: Nairaland Jamb Tutorial Centre {chemistry Thread} by boofydon: 7:15am On Dec 20, 2014

adebayour26:

lol
Calcium Oxide- CaO
Funny username.

it is her initials. Cao means Clara adaeze onazi. That's her name. she is a professional gamer, movie critic and base in england

(1) (2) (3) (4) (5) (6) (7) (8) (9) (Reply)

Beautiful Pictures Of Faith Academy Goshen(photos) / Obioma Somto Chants Igbo Kwenu On his Valedictory Address At Loyol Marymount Uni / Man Sends Young Groundnut Hawker Back To School (Photos)

(Go Up)

Sections: politics (1) business autos (1) jobs (1) career education (1) romance computers phones travel sports fashion health
religion celebs tv-movies music-radio literature webmasters programming techmarket

Links: (1) (2) (3) (4) (5) (6) (7) (8) (9) (10)

Nairaland - Copyright © 2005 - 2024 Oluwaseun Osewa. All rights reserved. See How To Advertise. 61
Disclaimer: Every Nairaland member is solely responsible for anything that he/she posts or uploads on Nairaland.