1.
The chemical element Astatine was discovered by:
Correct Answer
C. Emilio Segrè
Explanation
Emilio Segrè is the correct answer because he was one of the scientists who discovered the chemical element Astatine. Segrè was an Italian-American physicist who contributed to the discovery of several elements, including Astatine. He conducted research on the synthesis and identification of new elements, and in 1940, he successfully isolated Astatine for the first time. Segrè's work on Astatine and other elements earned him recognition and awards, including the Nobel Prize in Physics in 1959.
2.
Astatine has an atomic number of:
Correct Answer
B. 85
Explanation
Astatine has an atomic number of 85. The atomic number represents the number of protons in the nucleus of an atom. Astatine is a highly radioactive element with no stable isotopes, and its physical properties can vary depending on the specific isotope. Due to its scarcity and radioactivity, astatine is not found in nature in appreciable quantities and is primarily produced synthetically in laboratories for research purposes.
3.
The most stable isotope of Astatine has a half-life of:
Correct Answer
B. 8.1 hours
Explanation
Astatine is a highly radioactive element, and its most stable isotope, Astatine-210, has a half-life of 8.1 hours. This means that it takes 8.1 hours for half of a sample of Astatine-210 to decay into other elements. The longer the half-life, the more stable the isotope is. Therefore, the fact that Astatine-210 has a half-life of 8.1 hours indicates that it is relatively stable compared to other isotopes of Astatine.
4.
What is the chemical symbol of Astatine?
Correct Answer
B. At
Explanation
Astatine is a chemical element with the symbol At. It is a highly radioactive element and belongs to the halogen group on the periodic table. The symbol "At" is derived from its name "Astatine".
5.
The melting point of Astatine is:
Correct Answer
C. 302 °C
Explanation
The melting point of astatine is approximately 302°C (576°F). Astatine is a halogen, and as a member of Group 17 (VIIA) in the periodic table, it exhibits some similarities in properties to other halogens like fluorine, chlorine, bromine, and iodine. Astatine is a relatively rare and highly radioactive element, and due to its scarcity, its physical properties are not as well-determined as those of more abundant elements.
6.
Astatine has a boiling point of:
Correct Answer
A. 336.8 °C
Explanation
Astatine is a highly radioactive and scarce element, and its physical properties, including its boiling point, are not precisely known due to its limited availability and short half-life of its isotopes. However, estimates suggest that astatine's boiling point is expected to be around 337°C (639°F) under normal atmospheric pressure. Keep in mind that these values may vary due to the difficulties in studying astatine and the limited availability of stable isotopes for experimentation.
7.
Based on its chemical and physical properties, Astatine is a:
Correct Answer
C. Halogen
Explanation
Astatine is classified as a halogen based on its chemical and physical properties. Halogens are a group of highly reactive elements that are found in Group 17 of the periodic table. They have seven valence electrons, which makes them highly reactive and likely to form compounds with other elements. Astatine shares similar properties with other halogens like fluorine, chlorine, bromine, and iodine, such as high electronegativity and the ability to form stable halide compounds. Therefore, Astatine is correctly identified as a halogen.
8.
On the periodic table, Astatine is found in group:
Correct Answer
A. 17
Explanation
Astatine is found in group 17 on the periodic table. Group 17 is also known as the halogens, which are highly reactive nonmetals. Astatine is a rare and radioactive element that belongs to this group. It has properties similar to other halogens such as chlorine and iodine. Therefore, the correct answer is 17.
9.
How many neutrons does the most abundant isotope of Astatine have?
Correct Answer
C. 125
Explanation
Astatine has no stable isotopes, and its most abundant isotope is astatine-210. The isotope astatine-210 has 210 - 85 = 125 neutrons. The number 210 represents the total number of protons and neutrons in the nucleus, and since astatine has 85 protons (as indicated by its atomic number), subtracting the atomic number from the mass number gives the number of neutrons.
10.
The most stable isotope of Astatine is:
Correct Answer
C. A-210
Explanation
Astatine is a radioactive element, and its most stable isotope is A-210. This means that A-210 has the longest half-life compared to the other isotopes listed. A longer half-life indicates greater stability because it takes a longer time for half of the atoms in a sample to decay. Therefore, A-210 is the most stable isotope of Astatine among the options given.