The Mass of Thallium (Tl) on the Periodic Table Is

question 121

Multiple Choice

The mass of thallium (Tl) on the periodic table is given as 204.3833 without any units. There are 47 isotopes of thallium, but only two are stable and abundant, thallium-203, with a mass of 202.9723 amu, and thallium-205, with a mass of 204.9744 amu. What is the percentage of each of these isotopes in naturally occurring thallium?

• A)29.5% ²⁰³Tl and 70.5% ²⁰⁵Tl
• B)70.5% ²⁰³Tl and 29.5% ²⁰⁵Tl
• C)25.5% ²⁰³Tl and 74.5% ²⁰⁵Tl
• D)74.5% ²⁰³Tl and 25.5% ²⁰⁵Tl
• E)32.5% ²⁰³Tl and 67.5% ²⁰⁵Tl

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Definitions:

Neurotransmitters

Neurotransmitters are chemical messengers that transmit signals across a chemical synapse, from one neuron to another target neuron, muscle cell, or gland cell, facilitating communication within the brain and body.

Synaptic Activity

The process by which neurons communicate with each other through the release and reception of neurotransmitters across synapses.

Electroencephalogram (EEG)

A recording of neural activity detected by electrodes.

Electrodes

Conductive materials that are used to make electrical contact with a nonmetallic part of a circuit, such as the human body.