Problem 73 - Chemistry Matter and Change

Question

How many electrons, protons, and neutrons are contained in each atom? \begin{equation} \begin{array}{ll}{\text { a. }_{55}^{132} \mathrm{Cs}} & {\text { c. }_{69}^{163} \mathrm{Tm}} \\ {\text { b. }_{27}^{59} \mathrm{Co}} & {\text { d. }_{30}^{70} \mathrm{Zn}}\end{array} \end{equation}

Step-by-Step Solution

Answer

a. Cs: 55 electrons, 55 protons, 77 neutrons. b. Co: 27 electrons, 27 protons, 32 neutrons. c. Tm: 69 electrons, 69 protons, 94 neutrons. d. Zn: 30 electrons, 30 protons, 40 neutrons.

Step 1: Understand the Notation

The notation \({_Z^A}\text{Element}\) represents an atom where \(Z\) is the atomic number and \(A\) is the mass number. \(Z\) is equal to the number of protons, which also equals the number of electrons in a neutral atom, while \(A-Z\) gives the number of neutrons.

Step 2: Calculate Electrons, Protons, and Neutrons for Cesium (Cs)

For \({_{55}^{132} \text{Cs}}\), \(Z = 55\) and \(A = 132\). Thus, the number of:- Electrons = 55- Protons = 55- Neutrons = 132 - 55 = 77

Step 3: Calculate Electrons, Protons, and Neutrons for Cobalt (Co)

For \({_{27}^{59} \text{Co}}\), \(Z = 27\) and \(A = 59\). Thus, the number of:- Electrons = 27- Protons = 27- Neutrons = 59 - 27 = 32

Step 4: Calculate Electrons, Protons, and Neutrons for Thulium (Tm)

For \({_{69}^{163} \text{Tm}}\), \(Z = 69\) and \(A = 163\). Thus, the number of:- Electrons = 69- Protons = 69- Neutrons = 163 - 69 = 94

Step 5: Calculate Electrons, Protons, and Neutrons for Zinc (Zn)

For \({_{30}^{70} \text{Zn}}\), \(Z = 30\) and \(A = 70\). Thus, the number of:- Electrons = 30- Protons = 30- Neutrons = 70 - 30 = 40

Key Concepts

Atoms

Atoms are the basic units of matter and the defining structure of elements. They consist of three main components: protons, neutrons, and electrons. The central part of an atom is the nucleus, a dense core made up of protons and neutrons.
An atom's structure determines its chemical properties. The number of protons, known as the atomic number, defines the type of element. For example, all atoms with 55 protons are identified as cesium (Cs). Atoms are neutral overall because the number of positively charged protons equals the number of negatively charged electrons.
Understanding atoms is crucial because they form the building blocks of the universe. Comprehending how atoms interact leads to insights into chemical reactions and bonding, further explaining the vast world of compounds around us.

Protons

Protons are positively charged particles located within an atom's nucleus. Each proton carries a charge of +1.
The number of protons in an atom is known as its atomic number, denoted as 'Z'. This number is crucial for identifying an element, as every element on the periodic table has a unique atomic number.

• Proton Count: Determines the element type.
• Contributes to the atom's mass.

Besides contributing to an atom's identity, protons define its characteristics in terms of reactivity due to their influence on electron arrangement. The interaction between protons in the nucleus and surrounding electrons dictates the chemical behavior of atoms.

Electrons

Electrons are negatively charged particles that orbit the nucleus of an atom. Unlike protons and neutrons, electrons are not located in the nucleus; instead, they exist in an electron cloud surrounding it.
Each electron carries a charge of -1, effectively balancing the positive charge of a proton. This balance is what maintains the neutrality of an atom.

• Energy Levels: Electrons reside in energy levels or shells around the nucleus.
• Importance in Bonding: Electrons are crucial for determining how atoms will interact and bond with each other.
• Reactivity: The arrangement and movement of electrons define an element's reactivity and chemical properties.

Understanding electrons is vital since they take part directly in chemical bonding and reactions, dictating how substances interact.

Neutrons

Neutrons are neutral particles found in the nucleus of an atom, carrying no charge. Together with protons, they form the nucleus of an atom and contribute to its mass.

• Neutron Count: The number of neutrons in an atom can vary within the same element, leading to different isotopes which have different mass numbers, 'A'.
• Stability Influence: Neutrons contribute to the stability of an atom. They effectively balance the repulsive forces between positively charged protons, preventing the nucleus from breaking apart.
• Mass Difference: While they don't affect the charge of an atom, neutrons do add to its overall mass. The mass number, A, is the sum of protons and neutrons.

Understanding neutrons helps explain isotopes and nuclear behavior. Their role is crucial in understanding both atomic stability and the processes of nuclear reactions.