Answer:
The number of valence electrons in an atom is reflected by its position in the periodic table of the elements (see the periodic table in the Figure below). Across each row, or period, of the periodic table, the number of valence electrons in groups 1–2 and 13–18 increases by one from one element to the next
Answer: The concentration of hydroxide ions at this temperature is 
Explanation:
When an expression is formed by taking the product of concentration of ions raised to the power of their stoichiometric coefficients in the solution of a salt is known as ionic product.
The ionic product for water is written as:
![K_w=[H^+][OH^-]](https://tex.z-dn.net/?f=K_w%3D%5BH%5E%2B%5D%5BOH%5E-%5D)
![5.13\times 10^{-13}=[H^+][OH^-]](https://tex.z-dn.net/?f=5.13%5Ctimes%2010%5E%7B-13%7D%3D%5BH%5E%2B%5D%5BOH%5E-%5D)
As ![[H^+]=[OH^-]](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D%5BOH%5E-%5D)


The concentration of hydroxide ions at this temperature is 
Answer:
- 1 is the correct option
Explanation:
In determining the oxidation state or formal charge on element in an ionic specie, the whole ion need to be equated to the value of charge on the ion.
For example in this case, the charge on the ion is -3. Thus; representing iodine with X and putting -2 for the oxidation state of O (oxygen)
X + -2 = -3 (adding 2 to both side)
X = -3 + 2
X = - 1
Answer:
Percent error = -22%
Explanation:
Given data:
Density of aluminium = 2.1,2.12 and 2.09 g/cm³
Accepted value of density of aluminium = 2.7 g.cm³
Percent error = ?
Solution:
First of all we will calculate the average of data measured by students.
Average value = 2.1 g/cm³ + 2.12 g/cm³+ 2.09 g/cm³ / 3
Average value = 6.31 g/cm³/ 3
Average value = 2.1 g/cm³
Now we will calculate the percent error.
Percent error = [ Measured value - accepted value / accepted value ]× 100
Percent error = [ 2.1 g/cm³ - 2.70 g/cm³ / 2.70 g/cm³ ]× 100
Percent error = [-0.6/2.70 g/cm³ ] × 100
Percent error = -0.22 × 100
Percent error = -22%
Answer: Ionic bonds form only between metals and nonmetals. That's because metals “want” to give up electrons, and nonmetals “want” to gain electrons. It takes energy to remove valence electrons from an atom and form a positive ion. Energy is released when an atom gains valence electrons and forms a negative ion