ATOMIC STRUCTURE

/ Exams & Certification / By

ATOMIC STRUCTURE Homework# 3 Name Define the following: atomic number mass number isotope 2, What is the atomic number of titanium? How many protons does a titanium atom have? How many electrons does it have? 3. Give the mass number of each of the following atoms: beryllium with 5 neutrons b. titanium with 26 neutrons gallium with 39 neutrons iron with 30 neutrons Calcium-40 has protons, neutrons and electrons Tin-119 has protons, neutrons, and electrons_ 6. Carbon-13 has protons neutrons_ and electrons: 7. An element has 8 protons and 9 neutrons What element is it? b. How many electrons are in one atom of this element? What is its atomic mass? 8. An element has 46 neutrons and 36 electrons. a. How many protons are in one atom of this element? b. What is its atomic mass? What element is it? Suppose an element has 55 neutrons. Can you identify the element? Why not? or why 1G Find the average atomic mass for Li if 7.5% of Li atoms 6Li with a are

The Correct Answer and Explanation is:

Definitions:

  1. Atomic number (Z): The number of protons in the nucleus of an atom. It determines the element and its position in the periodic table. It also equals the number of electrons in a neutral atom.
  2. Mass number (A): The total number of protons and neutrons in an atom’s nucleus. It is used to identify isotopes of elements.
  3. Isotope: Atoms of the same element with the same number of protons but different numbers of neutrons. This results in different mass numbers.

Questions:

  1. Atomic number of Titanium:
    • The atomic number of titanium (Ti) is 22.
    • Since the atomic number represents the number of protons, a titanium atom has 22 protons.
    • In a neutral atom, the number of protons equals the number of electrons. Therefore, titanium also has 22 electrons.
  1. Mass numbers of the following atoms:
    a. Beryllium (Be) with 5 neutrons:
    • Atomic number of Be = 4 (4 protons)
    • Mass number A=protons+neutrons=4+5=9A = \text{protons} + \text{neutrons} = 4 + 5 = 9A=protons+neutrons=4+5=9
    • Mass number of Beryllium with 5 neutrons is 9.
    b. Titanium (Ti) with 26 neutrons:
    • Atomic number of Ti = 22 (22 protons)
    • Mass number A=22+26=48A = 22 + 26 = 48A=22+26=48
    • Mass number of Titanium with 26 neutrons is 48.
    c. Gallium (Ga) with 39 neutrons:
    • Atomic number of Ga = 31 (31 protons)
    • Mass number A=31+39=70A = 31 + 39 = 70A=31+39=70
    • Mass number of Gallium with 39 neutrons is 70.
    d. Iron (Fe) with 30 neutrons:
    • Atomic number of Fe = 26 (26 protons)
    • Mass number A=26+30=56A = 26 + 30 = 56A=26+30=56
    • Mass number of Iron with 30 neutrons is 56.
  1. Calcium-40:
    • Calcium (Ca) has 20 protons, since its atomic number is 20.
    • Calcium-40 means it has 40 – 20 = 20 neutrons.
    • Since it’s neutral, it has 20 electrons.
  1. Tin-119:
    • Tin (Sn) has 50 protons (atomic number 50).
    • Tin-119 means it has 119 – 50 = 69 neutrons.
    • It also has 50 electrons in a neutral atom.
  1. Carbon-13:
    • Carbon (C) has 6 protons (atomic number 6).
    • Carbon-13 means it has 13 – 6 = 7 neutrons.
    • It has 6 electrons in a neutral atom.
  1. Element with 8 protons and 9 neutrons:
    • The atomic number is 8, which corresponds to Oxygen (O).
    • Oxygen has 8 protons.
    • The number of electrons in a neutral atom of oxygen is also 8.
    • Its atomic mass (mass number) would be A=8+9=17A = 8 + 9 = 17A=8+9=17. So, the atomic mass is 17.
  1. Element with 46 neutrons and 36 electrons:
    a. Protons:
    • Since the number of electrons equals the number of protons in a neutral atom, this element has 36 protons.
    b. Atomic mass:
    • The mass number is A=36+46=82A = 36 + 46 = 82A=36+46=82.
    c. Element:
    • An element with 36 protons is Krypton (Kr).
  1. Can we identify the element with 55 neutrons?
    • No, we cannot identify the element with 55 neutrons alone.
    • The number of neutrons is insufficient to determine the element because the element’s identity is determined by its number of protons (atomic number). Different elements can have isotopes with various neutron numbers. We would need the number of protons (atomic number) to identify the element.
  1. Finding the average atomic mass for Li:
  • Lithium has two isotopes: 6Li^6Li6Li and 7Li^7Li7Li.
  • Given that 7.5% of Lithium atoms are 6Li^6Li6Li, we can assume that the remaining 92.5% are 7Li^7Li7Li.

To calculate the average atomic mass of Lithium: Average atomic mass=(0.075×6)+(0.925×7)\text{Average atomic mass} = (0.075 \times 6) + (0.925 \times 7)Average atomic mass=(0.075×6)+(0.925×7) Average atomic mass=0.45+6.475=6.925 amu\text{Average atomic mass} = 0.45 + 6.475 = 6.925 \, \text{amu}Average atomic mass=0.45+6.475=6.925amu

Related Posts

Scroll to Top