Question

Americium-241 is an isotope used in smoke detectors. What is the complete symbol for this isotope?

Short answer

The complete symbol for Americium-241 is \( _{95}^{241}\text{Am} \).

Step-by-step solution

Identify Atomic Number

Americium is a chemical element with the symbol Am and the atomic number of 95. This atomic number tells us the number of protons in the nucleus of the atom.

Identify the Mass Number

The given isotope is Americium-241, where 241 is the mass number. The mass number is the sum of protons and neutrons in the nucleus.

Construct the Complete Symbol

The complete symbol for an isotope includes the element symbol, the mass number (as a superscript), and the atomic number (as a subscript). The complete symbol is written as: \[ _{95}^{241}\text{Am} \] This indicates 95 protons (and electrons) and a total of 241 nucleons (protons + neutrons) in the nucleus.

Key concepts

Americium-241

Americium-241 is a specific isotope of the element americium, denoted as Am on the periodic table. This isotope is well-known for its use in household smoke detectors, making it quite relevant in our daily lives.
Each isotope of an element has the same number of protons but a different number of neutrons. For americium, the isotope referenced here is americium-241, where "241" refers to the mass number, which is the total number of protons and neutrons in its nucleus.
Americium-241 is radioactive, which is why it is effective in smoke detectors. It emits alpha particles that ionize the air inside the detector, allowing it to sense smoke particles. Despite its radioactivity, the amount used in smoke detectors is considered safe for home environments.

• Symbol: Am
• Used in: Smoke detectors
• Radioactive: Yes

Atomic Number

The atomic number is a fundamental concept in understanding elements on the periodic table. For americium, the atomic number is 95. This means that an americium atom has 95 protons in its nucleus, which also equals the number of electrons surrounding the nucleus in a neutral atom.
The atomic number is crucial because it determines the chemical properties of the element and its place on the periodic table. It's unique to each element, acting like an identity card for the atom. In isotope notation, the atomic number is typically written as a subscript on the lower left of the element symbol.

• Defines number of protons
• Identifies the element
• For americium: 95

Mass Number

Mass number is a significant detail in understanding isotopes. It is the sum of protons and neutrons present in an atom's nucleus. For americium-241, the mass number is 241. This is calculated by adding the 95 protons (atomic number) to the number of neutrons.
The mass number is crucial because it helps us differentiate between different isotopes of the same element. While isotopes have the same number of protons, they have varying numbers of neutrons, affecting the mass number.
In isotope notation, the mass number is written as a superscript on the upper left of the element's symbol.

• Sum of protons and neutrons
• Specific to isotopes
• For americium-241: 241

Nucleons

Nucleons are particles found within an atomic nucleus. They're mainly composed of protons and neutrons. Together, these particles determine most of an atom's mass, key to defining the properties of isotopes.
For instance, in americium-241, there are 241 nucleons in total, including both protons and neutrons. Since the atomic number (which is also the number of protons) is 95, it means there are 146 neutrons present (241 total nucleons - 95 protons). Understanding nucleons is essential as they contribute to both the stability and radioactive properties of an isotope.

• Include protons and neutrons
• Total equals mass number
• Crucial for isotope properties