2. The diagram below represents the bright-line spectra of four elements and a bright-line spectrum
produced by a mixture of two of these elements.
Which two elements are in this mixture?
(1) barium and hydrogen
(2) barium and lithium
(3) helium and hydrogen
(4) helium and lithium

How have the greenhouse gasses increased from the year 2000 to 2018

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?

Afusion reaction takes place between carbon and another element. neutrons are released, and a different element is formed. the different element is a) lighter than helium.b)heavier than helium.c)the same weight as helium.d)dependent on the element that reacted with carbon.