There are equal atoms of 20381Tl and 20581 Tl .Equal atoms of Superscript 203 Subscript; 81 Tl and Superscript 205 Subscript ; 81 Tl. There are___in a sample of thallium because the mass number of thallium, which is 204.38 a mu, is___the mass number of the isotope present in the highest percentage. In a sample of thallium because the mass number of thallium, which is 204.38 amu, is closer to.

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

space exploration has led to the development and technological improvement of many everyday items. (if this answer is wrong i will find the right answer) : )

> b takes place in the gas phase in an isothermal tubular reactor. the feed is one mole of a per one mole of c, an inert. the entering temperature and pressure are 427°c and 10 atm, respectively. the gas constant r = 0.08206 atm · l/mol · k.