Which of the following is part of the radius ratio rules?
1. Atoms are randomly placed.
2. Ions are hard spheres.
3. Atoms are spherical.
4. Atoms are rectangular.
5. All atoms never touch each other.
6. Cations and anions always touch each other.
7. Cation is surrounded by as many anions as possible to maximize stability.
Type in the appropriate number in the order given.
For example, if you think first, third and fifth properties are valid, you type 135 and not 153 or 531.
Which of the following is part of the radius ratio rules?
1. Atoms are randomly placed.
2. Ions are hard spheres.
3. Atoms are spherical.
4. Atoms are rectangular.
5. All atoms never touch each other.
6. Cations and anions always touch each other.
7. Cation is surrounded by as many anions as possible to maximize stability.
Type in the appropriate number in the order given.
For example, if you think first, third and fifth properties are valid, you type 135 and not 153 or 531.
The correct option is A 267
Let's look at the rules of radius ratios.
1. An anion and a cation are assumed to be hard spheres always touching each other.
2. Anions generally will not touch but may be close enough to be in contact with one another in a limiting situation.
3. A cation should surround itself with as many anions as possible. Each ion tends to surround itself with as many ions of opposite sign as possible to reduce the potential energy. This tendency promotes the formation of close-packed structures.
From the first rule, we can see that anions and cations or ions in general are assumed to be hard spheres.
It is also to be noted that anions and cations always touch each other while anions or cations may or may not touch each other, except under limiting conditions.
Also, the number of surrounding atoms of any cation or anion is as high as possible for maximum stability of the crystal.
So,
Atoms are randomly placed - is not part of the radius ratio rules
Ions are hard spheres - yes - 2
Atoms are spherical - in general yes, but not part of the radius ratio rules. We specifically talk about ions.
Atoms are rectangular - no way! – we assume that atoms are spheres here, and also for general purposes. We never assume that atoms are rectangular and probably never will!
8. All atoms never touch each other - Cations and anions always touch each other. That is one of the rules of radius ratios.
Cations and anions always touch each other - yes, always. - 6
Cation is surrounded by as many anions as possible to maximize stability - yes - 7
Let's look at the rules of radius ratios.
1. An anion and a cation are assumed to be hard spheres always touching each other.
2. Anions generally will not touch but may be close enough to be in contact with one another in a limiting situation.
3. A cation should surround itself with as many anions as possible. Each ion tends to surround itself with as many ions of opposite sign as possible to reduce the potential energy. This tendency promotes the formation of close-packed structures.
From the first rule, we can see that anions and cations or ions in general are assumed to be hard spheres.
It is also to be noted that anions and cations always touch each other while anions or cations may or may not touch each other, except under limiting conditions.
Also, the number of surrounding atoms of any cation or anion is as high as possible for maximum stability of the crystal.
So,
Atoms are randomly placed - is not part of the radius ratio rules
Ions are hard spheres - yes - 2
Atoms are spherical - in general yes, but not part of the radius ratio rules. We specifically talk about ions.
Atoms are rectangular - no way! – we assume that atoms are spheres here, and also for general purposes. We never assume that atoms are rectangular and probably never will!
8. All atoms never touch each other - Cations and anions always touch each other. That is one of the rules of radius ratios.
Cations and anions always touch each other - yes, always. - 6
Cation is surrounded by as many anions as possible to maximize stability - yes - 7
