Question

purpose: to observe and identify metallic ions using flame tests.
background: have you ever wondered why a candle flame is yellow? the characteristic yellow of a candle flame comes from the glow of burning carbon fragments. the carbon fragments are produced by the incomplete combustion reaction of the wick and candle wax. when elements, such as carbon, are heated to high temperatures, some of their electrons are excited to higher energy levels. when these excited electrons fall back to lower energy levels, they release excess energy in packages of light called photons, or light quanta. the color of the emitted light depends on its energy. blue light is more energetic than red light, for example. when an element emits a characteristic pattern of light energies, which is useful for identifying the element. the characteristic colors of light produced when substances are heated in the flame of a gas burner are the basis of flame tests for several elements.
in this experiment you will observe the color that various metallic elements impart to a bunsen flame. you will be able to identify unknown solutions using this technique.
pre - lab questions:

1. when the atom absorbs energy, the electrons move from their ____________ state to an __________ state. when an atom emits energy, the electrons move from a(n) __________ state to their __________ state and give off ____________.
2. is a flame test a qualitative or quantitative test for the identity of an unknown? explain.

Explanation:

Step1: Electron states and energy emission

When an atom absorbs energy, electrons move from their ground state (lowest energy state) to an excited state (higher energy state). When an atom emits energy, electrons move from an excited state to their ground state and give off light (photons).

Step2: Qualitative vs quantitative test

A flame test is a qualitative test. Qualitative tests are about identifying the presence or characteristics (like color in flame test which gives info about the element present) rather than measuring a quantity (like amount of a substance which would be quantitative).

Answer:

1. ground; excited; excited; ground; light (photons)
2. A flame test is a qualitative test. It identifies elements based on characteristic colors (qualitative characteristic) not on measuring a quantity.