Question

use the figures to answer the following questions. osmium 76 os 190.23 niobium 41 nb 92.906 27. what is the atomic number of osmium? 28. what is the chemical symbol for niobium? 29. what is the atomic mass of osmium? 30. what units is the atomic mass reported in? 31. how many protons and electrons does an osmium atom have? a niobium atom? calculate the atomic mass of each element described below. then use the periodic table to identify each element. 32. isotope mass (amu) percent abundance ⁶³x 62.930 69.17 ⁶⁵x 64.928 30.83 33. isotope mass (amu) percent abundance ³⁵x 34.969 75.77 ³⁷x 36.966 24.23

Explanation:

Step1: Identify atomic number of osmium

From the figure, the atomic number of osmium is 76.

Step2: Identify chemical symbol of niobium

From the figure, the chemical symbol of niobium is Nb.

Step3: Identify atomic mass of osmium

From the figure, the atomic mass of osmium is 190.23 amu.

Step4: Determine units of atomic mass

Atomic mass is reported in atomic mass units (amu).

Step5: Find number of protons and electrons in osmium and niobium

The number of protons in an atom is equal to its atomic number. In a neutral atom, the number of electrons is equal to the number of protons. For osmium with atomic number 76, it has 76 protons and 76 electrons. For niobium with atomic number 41, it has 41 protons and 41 electrons.

Step6: Calculate atomic mass for problem 32

The atomic mass ($A$) of an element with two isotopes is calculated using the formula $A = m_1\times p_1 + m_2\times p_2$, where $m_1,m_2$ are the masses of the isotopes and $p_1,p_2$ are their percent - abundances (in decimal form).
$p_1=0.6917$, $m_1 = 62.930$, $p_2=0.3083$, $m_2 = 64.928$
$A=62.930\times0.6917+64.928\times0.3083$
$A = 62.930\times0.6917=43.518681$
$A = 64.928\times0.3083 = 19.917202$
$A=43.518681 + 19.917202=63.435883\approx63.44$ (using periodic table, this is copper, Cu).

Step7: Calculate atomic mass for problem 33

$p_1 = 0.7577$, $m_1=34.969$, $p_2 = 0.2423$, $m_2=36.966$
$A=34.969\times0.7577+36.966\times0.2423$
$A=34.969\times0.7577 = 26.406011$
$A=36.966\times0.2423=8.957862$
$A=26.406011+8.957862 = 35.363873\approx35.45$ (using periodic table, this is chlorine, Cl).

Answer:

1. 76
2. Nb
3. 190.23 amu
4. atomic mass units (amu)
5. Osmium: 76 protons, 76 electrons; Niobium: 41 protons, 41 electrons
6. Atomic mass is approximately 63.44, element is Cu
7. Atomic mass is approximately 35.45, element is Cl