Chemistry: Post your doubts here!

[AbbbbY]

Hey can I get an A* in chem if I got A in P1 and P2 but D in practical? and how plzzzzz???

Depends paper to paper. Although practical is around 13% of the grade, it CAN cause a drop from an A* to an A. Best to prepare well for P4 and ace it (which is almost impossible). I screwed up a single question in my P4. Worth about 7-8 marks. Dropped that and around 3-4 others in the entire P4. Had a 60/60 P2. All components were A yet I didn't have an A*, so it depends on the percentile, really. People lose a lot of marks in P5 and P1.

 

[princess Anu]

What's the reason for Sodium and group 1 elements having a low melting point?

 

[Awesome12]

What's the reason for Sodium and group 1 elements having a low melting point?

When you go down the group, there will be more orbital shells. Thus, the outer-most (valence) electron shell will be subject to less electrostatic force attraction from the nucleus. Therefore, the valence electrons would be more free to move about. Metallic bonding is the force of attraction between the nucleus and the 'sea' of electrons, so the increased mobility of the valence electrons as it descends down the group will result in a weaker force of attraction. Thus, less energy will be required to overcome the forces of attraction.

 

[Dark Destination]

When you go down the group, there will be more orbital shells. Thus, the outer-most (valence) electron shell will be subject to less electrostatic force attraction from the nucleus. Therefore, the valence electrons would be more free to move about. Metallic bonding is the force of attraction between the nucleus and the 'sea' of electrons, so the increased mobility of the valence electrons as it descends down the group will result in a weaker force of attraction. Thus, less energy will be required to overcome the forces of attraction.

Doesn't answer her question.

 

[Awesome12]

Doesn't answer her question.

Enna tu Post-Corrector

 

[Dark Destination]

Enna tu Post-Corrector

Ena tu Nawaz Sharif.

The question was why do group 1 metals have low melting points, compared to other metals like Iron?

So what is your answer, Chemistry master?

 

[Awesome12]

princess Anu:

If by any chance you don't get what I have just wrote, then here is a simpler explanation

As we go down the group, the size of the atoms increases right? Thus the outer valence electron goes farther away from the nucleus (the nucleus is at the center). Metallic bonding involves the attraction between the valence of electrons and the nucleus. Since the valence electrons are farther away, there will be less attraction between the nucleus and the electrons. Kinda like a magnet and a strip of iron. The farther you take the strip from the magnet, the weaker the attraction. Since the attraction is weaker, less energy is required to overcome the forces of attraction.

 

[MarcoReus]

So, you people did start studying A Levels in the holidays. :v

 

[Awesome12]

So, you people did start studying A Levels in the holidays. :v

No we didn't. It was just an O level concept.

 

[umer salman]

can any one help me i want chemistry alevel cie papers , all for them combined <latest pastpapers> mcqs,theory and practical

 

[MarcoReus]

How many years?

 

[muhammadali233]

How many years?

ap ka kya haal hai?

 

[MarcoReus]

Fit. Agye humare exclusive past paper compiler.

 

[muhammadali233]

Fit. Agye humare exclusive past paper compiler.

Haan chalein me kuch hoon,ap ka plan tu fail ho gya,khair choren purni baton ko,parhai kaisi ho rahi hai?

 

[umer salman]

at-least 5 years

 

[umer salman]

How many years?

around 5 years .plus it would be good if u get me the physics ones too
but thank u for replying

 

[Uchiha-Sasuke]

The structure already shows CH3 and H.
You need to complete it using the following:
H2N
HO2C
H
OH

kasmay? XD

princess Anu:

If by any chance you don't get what I have just wrote, then here is a simpler explanation

As we go down the group, the size of the atoms increases right? Thus the outer valence electron goes farther away from the nucleus (the nucleus is at the center). Metallic bonding involves the attraction between the valence of electrons and the nucleus. Since the valence electrons are farther away, there will be less attraction between the nucleus and the electrons. Kinda like a magnet and a strip of iron. The farther you take the strip from the magnet, the weaker the attraction. Since the attraction is weaker, less energy is required to overcome the forces of attraction.

adding to what he said ^ atomic size decreases left to right in the peri table (that's why group 1 elements have bigger sized atoms comparatively)

 

[MarcoReus]

kasmay? XD

adding to what he said ^ atomic size decreases left to right in the peri table (that's why group 1 elements have bigger sized atoms comparatively)

Your avatar is awesome. So much win!

I so loved how he put Kakashi through 3 days of illusioned pain and then said "Only 71 hours, 59 minutes and 59 seconds to go".

 

[Uchiha-Sasuke]

Your avatar is awesome. So much win!

I so loved how he put Kakashi through 3 days of illusioned pain and then said "Only 71 hours, 59 minutes and 59 seconds to go".

<----bruv it's sasugay not itachi

 

[MarcoReus]

Sorry. I meant signature. :/

I thought I edited that - probably didn't process or something.