## diatomic elements

Leslie Cheng 4B
Posts: 35
Joined: Fri Sep 28, 2018 12:29 am

### diatomic elements

Hi! Can someone explain to me why diatomic elements form, and how to distinguish between whether an element is existing in its diatomic form or not? For example, if a problem involves a diatomic element like oxygen, do you assume that's in a diatomic form, or does the problem have to state explicitly "oxygen gas"?

Erin Kim 2G
Posts: 75
Joined: Fri Sep 28, 2018 12:26 am

### Re: diatomic elements

All the elements in the acronym HOFBrINCl, (hydrogen, oxygen, fluorine, Bromine, Iodine, and chlorine) are included in the diatomic elements. Any time these elements are listed in a chemical equation they must have the subscript of 2 as you always assume they are diatomic.

Elias Omar 1G
Posts: 52
Joined: Fri Sep 28, 2018 12:17 am

### Re: diatomic elements

The reason these elements are diatomic is because they don't have enough electrons to fill up their valence shells. Thus, they cannot exist as a single atom.

Ashish Verma 2I
Posts: 59
Joined: Fri Sep 28, 2018 12:28 am

### Re: diatomic elements

One cheap mnemonic device to remember these is: Never Have Fear Of Ice CoLd Bread
Never: $N_2$ Nitrogen
Have: $H_2$ Hydrogen
Fear: $F_2$ Fluorine
Of: $O_2$ Oxygen
Ice: $I_2$ Iodine
CoLd: $Cl_2$ Chlorine
Bread: $Br_2$ Bromine

Ester Garcia 1F
Posts: 29
Joined: Fri Sep 28, 2018 12:17 am

### Re: diatomic elements

My TA taught us another method to remember the diatomic elements. She refers to them as gens and ines. Ex. HydroGEN and fluorINE

AJ Manzano 3K
Posts: 16
Joined: Fri Sep 28, 2018 12:25 am

### Re: diatomic elements

For me, it helps when I picture them on the periodic table because, with the exception of Hydrogen, the other six elements (C, N, O, F, Cl, Br, I) border the top right hand corner of the table next to the column of noble gases.

inlovewithchemistry
Posts: 104
Joined: Fri Sep 28, 2018 12:19 am

### Re: diatomic elements

In high school, we learned to remember them with a phrase pronounced "Br-inkl-hoff," which is Br(bromine), I(iodine), N (nitrogen), Cl(chlorine), H(hydrogen), O(oxygen), and F(fluorine). Helped me a lot back then and now.

Aili Ye 4L
Posts: 58
Joined: Fri Sep 28, 2018 12:16 am

### Re: diatomic elements

Some elements exist as diatomic elements since in their original state, their valence shells are not filled, thus they share electrons between each other and thus fill their shells and achieve a state of lower energy.

Andrew Lam 3B
Posts: 30
Joined: Fri Sep 28, 2018 12:24 am

### Re: diatomic elements

Diatomics exist to share electrons covalently and achieve a lower energy state.

HOFBrINCl is a metonym to remember the diatomics:
H- Hydrogen
O- Oxygen
F- Fluorine
Br- Bromine
I- Iodine
N- Nitrogen
Cl- Chlorine

Karina Jiayu Xu 4E
Posts: 58
Joined: Fri Sep 28, 2018 12:29 am

### Re: diatomic elements

Does anyone know what order to put the elements in when writing an empirical formula?

Rhea Churi 4K
Posts: 62
Joined: Fri Sep 28, 2018 12:28 am

### Re: diatomic elements

Karina Jiayu Xu 4E wrote:Does anyone know what order to put the elements in when writing an empirical formula?

In an empirical formula, it's typically C, H, and then other elements follow in alphabetical order.

yuetao4k
Posts: 60
Joined: Fri Sep 28, 2018 12:27 am
Been upvoted: 1 time

### Re: diatomic elements

Diatomic elements only need to exist in pairs of atoms when they are standing alone. For instance, in OH-, you wouldn't need two hydrogen atoms because the hydrogen is not free standing. However, if you have hydrogen gas, you would need H2 because it is not attached to a different element.

705022748
Posts: 26
Joined: Fri Sep 28, 2018 12:25 am

### Re: diatomic elements

Elements are diatomic because their valence shells aren't completely filled by electrons; therefore, electrons are shared a lower energy state is achieved.