In class during chemistry lesson
Teacher: good morning
student
Student: good morning
miss
Teacher: okay we will
start today's lesson. Today we will discuss about alkaline elements. Does
anyone know what an alkaline element is?
Wulan: I know miss,
Alkali metal is a group of chemical elements in Group 1 of periodi table
Teacher: Well the
answer is correct. Thus Alkali metals are a group of chemical elements in Group
1 of the periodic table, except hydrogen. This group consists of: lithium (Li),
sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and franium (Fr). All
the elements in this group are so reactive that they are naturally never found
in a single form. To inhibit reactivity, alkali metal elements must be stored
in the oil medium.
Pipit: miss why
alkaline element is very reactive?
Teacher: is there
anyone who can answer the question from the pipit?
Nanda: I miss,
according to the book I read The element of Alkali belongs to the reactive
element group, because the Alkali element is very easy to release the valence
electrons on the skin
Wulan: miss I think
Alkali metals are very reactive because in their outermost shells they have
only one electron and this causes the Alkali metals to become very unstable
(stable if 2 or 8)
Teacher: nah student,
all the answers from your friends are correct, so alkaline element is very
reactive because caused ease of release valence electron on skin ns1 form
compound with +1 oxidation number. Therefore, the elements of alkali metal are
not found as free metal in nature, but are in the form of compounds. Do the
sparrows and others already understand?
Student: yes miss we
already understand (in answer simultaneously)
Teacher: next All
elements of class IA are silvery white in solid metal form, except cesium in
liquid form at room temperature. Alkali metal Sodium is a soft metal and can be
cut with a knife. Alkali metal Potassium is softer than sodium. Physical
properties of alkali metals such as soft with low melting points. Alkali metals
are the most powerful reducing agents, as indicated by a negative standard
reduction potential.
Wulan: miss why low
alkali metal melting point?
Teacher: is there any
answer from wulan question?
Student: do not know
miss (answered in unison)
Teacher: low melting
point becomes an indication that antagonic metal bond in alkali is very weak.
This is due to the atomic radius of alkali metal is relatively large compared
to other elements in one period. The decrease in the melting point of the
lithium alkali metal to cesium is due to the radius of the larger atom thus
reducing the bonding strength of the metal antaratome
Nanda: miss whether
alkali element is useful in everyday life?
Teacher: good question
nanda. Many alkaline elements are used as lubricants, batteries, glass
industry, alloy materials in tin, aluminum, and magnesium which are
reinforcing. For example Sodium: Sodium or also known as sodium have many
benefits for humans such as: Sodium Nitrate is the main material of making
gunpowder, Sodium Sulfate Compound, Sodium Carbonate, and Sodium Hydroxide
widely used in the paper industry, Sodium Carbonate is used as absorbent
Pollutants from factory chimneys. Selin is also used in glass and detergent
industry, Kitchen Salt (Sodium Chloride) widely used for various dishes, Baking
Soda (Sodium Bicarbonate) is used as a cake developer. Potassium (Potassium) is
also used for example: Potassium is widely used as a fertilizer maker,
Potassium Hydroxide is used in Detergent and Potassium Bromide industry used in
photography. In addition to the above three metals, there is still cesium that
can be utilized in radiation detection equipment.
Student: oh means the
alkali element is very useful ya miss?
Teacher: yes alkali
element is useful in human life. Can anyone conclude today's material?
Rena: I miss in my
opinion today's conclusion Alkali metals are a group of chemical elements in
Group 1 of the periodic table, except hydrogen. This group consists of: lithium
(Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and franium (Fr)
Pipit: so alkaline
element is very reactive because caused ease of release valence electrons on
skin ns1 form compound with +1 oxidation number
Wulan: Alkaline
element Widely used as a lubricant, battery, glass industry, alloy materials in
tin, aluminum, and magnesium are reinforcing. So the alkaline element is very
useful in human life
Teacher: Well, all the
conclusions are pretty good. Do you understand about today's lesson?
Student: already miss
(in reply synchronously)
Teacher: okay because our time is up, we continue
next week, for next week's material the students will be divided into small
groups so prepare yourself as best as possible, for members of his group will
be in further notice. See you next week
Student: yes miss, see you too
Since the time was up, the Master left the class room
How electronegativity of alkalinity?
BalasHapusIn the alkali metal class, from top to bottom in the periodic system, electronegativity decreases. This is because the size of the atom (atomic radius) is greater so that the valence electron away from the metal core. The result is less attracted to the metal core. Although from top to bottom the nuclear charge increases, but the effect of this increase in core charge is lost by the effect of increasing the size of the atom
HapusWhat is the different between Na and K?
BalasHapusPotassium is a chemical element in the periodic table that has the symbol K and atomic number 19. Potassium is soft silvery-white metal and belongs to the alkaline earth group. Naturally, potassium is found as a compound with other elements in seawater or other minerals while sodium or sodium is a chemical element in the periodic table having Na symbols and atomic number 11. Sodium is a soft, silvery reactive, and waxy reactive metal, which includes To alkali metals which are widely present in natural compounds (especially halite). He is very reactive, the flame is yellow, oxidizes in air, and reacts strongly with water, so it must be stored in oil.
HapusWhat can we do if the student keep not understand what we said?
BalasHapusIf I as a teacher if the students do not understand or not understand that I explain then I will repeat explain the material that he has not understood with more details with also give understanding to students who already understand that their friends need to repeat the material again so that those who already understand not bored With repetitive material. Then after I explain again I will give an example and ask them to write it in front so they get used to the problems that exist so they will be more understanding and can apply the material to do the questions
HapusWhat is gunpowder and what is its use?
BalasHapusGunpowder or black powder is an explosive material made from a mixture of sulfur, charcoal, and potassium nitrate, which burns very quickly and the propellers in firearms and fireworks. Gunpowder is classified as a weak explosive because of its low explosive power. The resulting explosion made subsonic waves, not supersonic waves like those produced by powerful explosives. The movement of the gas produced by gunpowder explosion produces enough pressure to fire a Peruvian child, but will not destroy the barrel.
HapusWhy hydrogen is not an alkaline class?
BalasHapusH or Hydrogen is not included in the alkali metal group because it has no alkali metal characteristics. Alkali metals can be seen in the periodic table in Group 1A consisting of Lithium (Li), Narium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Fransium (Fr). Although hydrogen is also present in Group 1A, but hydrogen is not included in the alkali metal group. Hydrogen is a water-forming element in which if hydrogen is solidified in a certain concentration they will form a water point. Alkali metals are characteristic if they are reacted with water they will form alkaline hydroxide ions with a pH of more than 7. While hydrogen is the water itself and if reacted with water will not cause any change.
Hapus