Complete each of the statements a to d using 1, 2, or 3:

1. decreases

2. increases

3. remains the same

Going from left to right across Period 4,

d. the number of valence electrons ________

Which statements completed with a to e will be true and which will be false?

An atom of N compared to an atom of Li has a larger (greater)

b. ionization energy

Which statements completed with a to e will be true and which will be false?

An atom of N compared to an atom of Li has a larger (greater)

c. number of protons

Use Rutherford's gold-foil experiment to answer each of the following:

b. How did the results differ from what he expected?

Use Rutherford's gold-foil experiment to answer each of the following:

c. How did he use the results to propose a model of the atom?

Match the subatomic particles (1 to 3) to each of the descriptions below:

1. protons

2. neutrons

3. electrons

b. surround the nucleus

Consider the following atoms in which X represents the chemical symbol of the element:

¹⁶₈X ¹⁶₉X ¹⁸₁₀X ¹⁷₈X ¹⁸₈X

a. What atoms have the same number of protons?

Consider the following atoms in which X represents the chemical symbol of the element:

¹⁶₈X ¹⁶₉X ¹⁸₁₀X ¹⁷₈X ¹⁸₈X

c. Which atoms have the same mass number?

Consider the following atoms in which X represents the chemical symbol of the element:

¹⁶₈X ¹⁶₉X ¹⁸₁₀X ¹⁷₈X ¹⁸₈X

d. What atoms have the same number of neutrons?

Indicate if the atoms in each pair have the same number of protons, neutrons, or electrons.

c. ⁴⁰₁₈Ar, ³⁹₁₇Cl

Complete the following table for the three naturally occurring isotopes of silicon, the major component in computer chips:

For each representation of a nucleus A through E, write the atomic symbol and identify which are isotopes.

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Indicate if each of the following statements is true or false:

c. The atomic mass unit is based on a carbon atom with six protons and six neutrons.

Indicate if each of the following statements is true or false:

d. The proton and the electron have about the same mass.

Write the name and symbol of the element with the following atomic number:

h. 92

Why is the ionization energy of Ca higher than K, but lower than that of Mg?

Why is the ionization energy of Cl lower than F, but higher than that of S?

Give the symbol of the element that has the

e. most metallic character in Group 2A (2)

Give the symbol of the element that has the

a. largest atomic size in Group 1A (1)

Give the symbol of the element that has the

b. largest atomic size in Period 4

Give the symbol of the element that has the

e. least metallic character in Group 4A (14)