Question

Radon is a radioactive gas that can cause lung cancer. It has been detected in the basements of some homes. How many protons are there in a Rn-220 atom? How many neutrons?

Short answer

Answer: A Radon-220 atom has 86 protons and 134 neutrons.

Step-by-step solution

Find the atomic number of Radon

Radon is abbreviated as "Rn" on the periodic table. To find its atomic number, look up its position on the periodic table. Radon is in group 18 and period 6. The atomic number of Radon is 86, which means it has 86 protons in its nucleus.

Calculate the number of neutrons in Rn-220

To find the number of neutrons in a Rn-220 atom, we can use the formula: Number of neutrons = Atomic mass number - Number of protons In this case, the atomic mass number of Rn-220 is 220, and the number of protons is 86. Plugging these values into the formula, we get: Number of neutrons = 220 - 86 Number of neutrons = 134 There are 134 neutrons in a Rn-220 atom. So, a Rn-220 atom has 86 protons and 134 neutrons.

Key concepts

Understanding the Atomic Number

The atomic number is a fundamental characteristic of any chemical element, defining its identity as well as distinct place within the periodic table. For an element like Radon (Rn), the atomic number is of particular interest as this noble gas has significant radioactive properties. But what exactly is the atomic number?

The atomic number, denoted by the letter 'Z', represents the number of protons in the nucleus of an atom. Protons carry a positive charge, and because atoms are neutral overall, the number of protons also dictates the number of electrons orbiting the nucleus. This balance between protons and electrons shapes the chemical behavior of the element.

For instance, in Radon, the atomic number of 86 means that there are 86 protons in its nucleus. This directly tells us that there are also 86 electrons around the nucleus, maintaining the charge balance and influencing its interaction with other atoms. This is crucial when discussing Radon's radioactive nature which goes hand in hand with its decay processes.

Calculating Neutrons in an Atom

When it comes to finding the number of neutrons in an atom, knowing how to perform a neutron calculation is essential. This process starts with two basic properties of an atom: the atomic number, as previously discussed, and the atomic mass number. The atomic mass number, represented by the letter 'A', is the sum of protons and neutrons in the nucleus.

Here’s how one can calculate the number of neutrons:

• Determine the atomic number (number of protons).
• Find the atomic mass number (often close to the atomic weight and usually represented as a whole number).
• Subtract the atomic number from the atomic mass number: \( \text{{Number of neutrons}} = A - Z \).

The exercise given regarding Radon's Rn-220 isotope requires such a calculation. With an atomic mass number of 220 and an atomic number of 86, it’s a straightforward subtraction: \( 220 - 86 = 134 \) neutrons. These neutrons, along with the protons, complete the atomic nucleus and play a vital role in the stability of the atom.

Exploring the Periodic Table

The periodic table is an organized chart that displays all recognized chemical elements in an ordered, systematic layout. It isn't just a list but a powerful tool that reflects the underlying principles of chemistry, such as the periodicity of element properties.

Elements in the periodic table are arranged in rows called periods and columns known as groups or families. The positions convey significant information:

• Vertical arrangement (Groups): Elements in the same group typically have similar chemical properties and the same number of outermost electrons.
• Horizontal arrangement (Periods): Indicates increasing atomic numbers from left to right and defines some of the physical characteristics due to the electron configuration.

Radon, found in group 18 and period 6 of the periodic table, belongs to the noble gases family which are known for their low reactivity due to having a complete outer electron shell. This position tells chemists about its reactivity, common compounds, and even its state of matter. Understanding the periodic table is not just about memorizing element names and symbols; it's about comprehending the interplay of atomic structures that define the natural world.