Quimica.

a) The effect of the light over valence electrons

It’s called “The photoelectric effect”, is the emission of electrons from a material when it is incident by an electromagnetic radiation (visible or ultraviolet light in general)

b) What is an emission spectrum?

An emission spectrum is the electromagnetic radiation (EMR), such as visible light, a substance emits. Every element gives off a unique fingerprint of light, so analyzing the frequencies of this light helps identify the chemical that generated it. This procedure is called emission spectroscopy and is a very useful scientific tool.

c) The typical colors of a flame in relation to different elements

Symbol

Name

Color

Image

As

Arsenic

Blue

B

Boron

Bright green

Ba

Barium

Pale/Apple green

Ca

Calcium

Brick red

Cs

Caesium

Blue-Violet

Cu(I)

Copper(I)

Bluish-green

Cu(II)

Copper(II) (non-halide)

Green

Cu(II)

Copper(II) (halide)

Blue-green

Fe

Iron

Gold

In

Indium

Blue

K

Potassium

Lilac

Li

Lithium

Red

Mn (II)

Manganese (II)

Yellowish green

Mo

Molybdenum

Yellowish green

Na

Sodium

Intense yellow

P

Phosphorus

Pale bluish green

Pb

Lead

Blue/white

Ra

Radium

Crimson red

Rb

Rubidium

Red-violet

Sb

Antimony

Pale green

Se

Selenium

Azure blue

Sr

Strontium

Crimson

Te

Tellurium

Pale green

Tl

Thallium

Pure green

Zn

Zinc

Colorless (sometimes reported as bluish-green)

MATERIALS:

1. Inoculation loop or a graphite of a pencil

2. 8 test tubes

3. Rack

4. Beaker

5. Cobal filter

6. Bunsen burner

PROCEDURE

1) Place a little quantity of the salts from the test tubes, but big enough to take samples with the inoculation loop.

2) Wash the inoculation loop in 15ml in the hydrochloric acid solution poured in a beaker.

3) Introduce the graphite in the tube that contains some metallic salt in order to take a little sample from it and heat it using the Bunsen burner.

4) Record your observations about the flame color. Repeat

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