Respuesta :
Answer:
Explanation:
a) chalcogens are elements of group 16 of periodic table.
Tellurium have mass no 125. atomic no 52 so ¹²⁵Te₅₂ is the symbol .
b) halogen ( group 17 elements) radioactive isotope is astatine
atomic no is 85 and mass no may be 210 ( most stable) ²¹⁰At₈₅
c) neon gas is used in lighting .It is a noble gas .
²⁰Ne₁₀ is the symbol
d) lightest alkali metal Beryllium ( Be) .Isotope having 3 neutrons is
⁷Be₄ .
Answer:
(a) [tex]^{125} _{52}Te[/tex]
(b) [tex]^{210} _{85}At[/tex]
(c) [tex]^{20} _{10}Ne[/tex]
(d) [tex]^{6} _{3}Li[/tex]
Explanation:
Write a symbol for each of the following neutral isotopes. Include the atomic number and mass number for each.
(a) the chalcogen with a mass number of 125
Chalcogens are the elements in the Group 16 in the Periodic Table. Tellurium has an average atomic mass of 127.6 u so it must be an isotope of it. The atomic number of Te is 52. The symbol is [tex]^{125} _{52}Te[/tex].
(b) the halogen whose longest-lived isotope is radioactive
Halogens are the elements in the Group 17 of the Periodic Table. The atom whose longest-lived isotope is radioactive is astatine, with a mass number = 210 and an atomic number = 85. The symbol is [tex]^{210} _{85}At[/tex].
(c) the noble gas, used in lighting, with 10 electrons and 10 neutrons
The noble gas used in lighting is neon, with 10 protons (atomic number = 10), 10 electrons and 10 neutrons (mass number = 10 p⁺ + 10 n⁰ = 20). The symbol is [tex]^{20} _{10}Ne[/tex].
(d) the lightest alkali metal with three neutrons
Alkali metals are the elements in the Group 1 in the Periodic Table. The lightest one is lithium with 3 protons (atomic number = 3). The isotope with 3 neutrons has a mass number = 3 p⁺ + 3 n⁰ = 6. The symbol is [tex]^{6} _{3}Li[/tex].
