What is a decay chain
a. one element decaying into another, which decays into another
b. a list of radioactive substances organized by atomic weights
c. an accumulation of particles emitted through radioactive decay
d. a list of radioactive substances organized by half life times
please help tysm

Write the symbol for every chemical element that has atomic number greater than 3 and atomic mass less than 12.0 u.

Malik formed a hypothesis that an increase in atmospheric oxygen levels by 10% would cause red-legged grasshoppers to grow larger than normal. suppose that malik performs an experiment to test his hypothesis. which of these actions would represent a scientific mistake in his experiment? a. he experiments on live grasshoppers instead of preserved ones. b. he focuses on red-legged grasshoppers instead of all kinds of grasshoppers. c. he varies the nitrogen and carbon dioxide levels in the air from one trial to the next. d. he conducts the experiment in a controlled lab setting with a lab partner. e. he measures the mass and length of his specimens at the start of each trial.

Use the bond energies provided to estimate δh°rxn for the reaction below. ch3oh(l) + 2 o2(g) → co2(g) + 2 h2o(g) δh°rxn = ? bond bond energy (kj/mol) c-h 414 c-o 360 c=o 799 o=o 498 o-h 464 use the bond energies provided to estimate δh°rxn for the reaction below. ch3oh(l) + 2 o2(g) → co2(g) + 2 h2o(g) δh°rxn = ? bond bond energy (kj/mol) c-h 414 c-o 360 c=o 799 o=o 498 o-h 464 +473 kj +206 kj -392 kj -91 kj -486 kj