Question

1. based on the periodic table, which other element is likely to share common properties with sodium, or na?

a. ca
b. cs
c. mg
d. ne

1. which of the following is a characteristic of the group 14 elements?

a. they have 14 protons.
b. they have 14 neutrons.
c. they have 4 core electrons.
d. they have 4 valence electrons.

1. an atom of bromine has 35 electrons. these electrons are present in energy shells around the nucleus. which choice lists the number of electrons that appear in the energy shells of a bromine atom, starting with the number of electrons in the energy shell closest to the nucleus?

a. 2, 8, 18, 1
b. 2, 8, 18, 7
c. 2, 8, 18, 35
d. 2, 8, 8, 17

Explanation:

2.

Step1: Analyze the group of sodium

Sodium (Na) is in Group 1 (alkali metals) of the periodic table. Elements in the same group have similar properties.

Step2: Check the groups of each option

• Calcium (Ca) is in Group 2.
• Cesium (Cs) is in Group 1.
• Magnesium (Mg) is in Group 2.
• Neon (Ne) is in Group 18 (noble gases).

3.

Step1: Recall the properties of Group 14 elements

Group 14 elements have 4 valence electrons.

Step2: Analyze each option

• Option A: The number of protons is equal to the atomic number. Group 14 elements have different atomic numbers (e.g., C has atomic number 6, Si has atomic number 14).
• Option B: The number of neutrons varies for different isotopes of Group 14 elements.
• Option C: Core electrons are not a defining characteristic for the group.
• Option D: Group 14 elements have 4 valence electrons.

4.

Step1: Use the electron - shell filling rules

The first shell (K - shell) can hold a maximum of 2 electrons.
The second shell (L - shell) can hold a maximum of 8 electrons.
The third shell (M - shell) can hold a maximum of 18 electrons.
The fourth shell (N - shell) is filled next.
For bromine (\(Br\)) with \(Z = 35\) (number of electrons = 35):

• First shell: 2 electrons.
• Second shell: 8 electrons.
• Third shell: 18 electrons.
• Fourth shell: \(35-(2 + 8+18)=7\) electrons.

Answer:

1. B. Cs
2. D. They have 4 valence electrons.
3. B. 2, 8, 18, 7