Question

1. element x is in the alkaline earth metals family. which element would have properties most similar to element x? a. xenon b. strontium c. rubidium d. sulfur 2. what group of the periodic table does this atom belong to? a. alkali metals b. alkaline earth metals c. halogens d. noble gases 6. which two structural characteristics of atoms determine the placement of elements on the periodic table? a. ionization and electrons in the nucleus b. energy level of the neutrons and number of electrons in the nucleus c. energy level of the valence electrons and number of protons in the nucleus d. ionization and the neutrons found in the nucleus 7. the nucleus of an atom has all of the following characteristics except that it a. is positively charged b. is very dense c. contains nearly all the atom’s mass d. contains nearly all the atom’s volume 8. calculate the atomic mass of the element x. then use the periodic table to identify the element. isotope mass (amu) percent abundance x - 28 27.9770 92.23 x - 29 28.9765 4.67 x - 30 29.9738 3.10

Explanation:

Step1: Solve question 4

Elements in the same group have similar properties. Alkaline - earth metals are in group 2. Strontium is in group 2. Xenon is a noble - gas, Rubidium is an alkali metal, and Sulfur is a non - metal. So the element with properties most similar to an alkaline - earth metal is Strontium.

Step2: Solve question 2

The number of protons ($p^+$) is 12. The element with 12 protons is Magnesium, which is in group 2 (alkaline - earth metals).

Step3: Solve question 6

The placement of elements on the periodic table is determined by the energy level of the valence electrons and the number of protons (atomic number) in the nucleus.

Step4: Solve question 7

The nucleus is positively charged (due to protons), very dense, and contains nearly all the atom's mass. But it does not contain nearly all the atom's volume. The electrons occupy most of the atom's volume.

Step5: Solve question 8

The atomic mass ($A$) of an element is calculated using the formula $A=\sum_{i}m_i\times \%_i$, where $m_i$ is the mass of an isotope and $\%_i$ is its percent abundance.
\[

$$\begin{align*} A&=(27.9770\times0.9223)+(28.9765\times0.0467)+(29.9738\times0.0310)\\ &=(27.9770\times0.9223)+(28.9765\times0.0467)+(29.9738\times0.0310)\\ &=25.803+1.3532+0.9292\\ &=28.0854\approx28.09 \end{align*}$$

\]
The element with an atomic mass close to 28.09 is Silicon.

Answer:

1. b. Strontium
2. b. Alkaline earth metals
3. c. Energy level of the valence electrons and number of protons in the nucleus
4. d. contains nearly all the atom’s volume
5. The atomic mass is approximately 28.09 and the element is Silicon.