Question

the data below shows the successive ionization energies for unknown element, r. use the data to answer the questions below.
successive ionization energies (kj/mol)
1st 786.3
2nd 1,580
3rd 3,230
4th 4,360
5th 16,000
6th 20,000

1. **if this element is found in period 3, what is its likely identity?

a. sodium e. phosphorus
b. magnesium f. sulfur
c. aluminum g. chlorine
d. silicon h. argon

1. **explain your response to q1 using coulombs law:
2. explain the following observations in terms of atomic structure and periodicity.

a. ca has a lower second ionization energy than k.

Explanation:

Step1: Analyze ionization energy jumps

Ionization energy is the energy required to remove an electron from an atom. A large jump in ionization energy indicates that a core electron is being removed. For the given data, there is a large jump between the 4th and 5th ionization energies. This means that the element has 4 valence electrons.

Step2: Identify the element in Period 3 with 4 valence electrons

In Period 3, the elements have the following valence electrons:

• Sodium (Na): 1 valence electron
• Magnesium (Mg): 2 valence electrons
• Aluminum (Al): 3 valence electrons
• Silicon (Si): 4 valence electrons
• Phosphorus (P): 5 valence electrons
• Sulfur (S): 6 valence electrons
• Chlorine (Cl): 7 valence electrons
• Argon (Ar): 8 valence electrons (stable octet, very high ionization energies)

Since the element has 4 valence electrons and is in Period 3, it is silicon.

Answer:

d. silicon