What information does the main group number provide?
The main group number corresponds to the number of outer electrons (valence electrons) of the respective atom. The periodic table of the elements shows that carbon atoms have four outer electrons (Figure 2) and aluminum atoms have three outer electrons (Figure 3).
What similarities do elements of the same period have in common?
According to the shell model, the elements of a period occupy the same electron shell. These shells are named K, L, M, N, O, P, and Q, from the inside out.
How do the properties change within the periodic table?
This also explains the change in the properties of the elements within the periodic table. However, the nuclear charge increases by one unit (one proton) with each element. Consequently, the attraction of the electrons by the positively charged nucleus also increases within a period.
What do elements in a group have in common?
In the main groups, the number of electrons in the outer electron shell of all elements is identical. In the subgroups that only contain metallic elements, the outer shell usually has two electrons; here the underlying shell is decisive for the chemical properties of the element.
What do the noble gases have in common?
The noble gases include the elements helium, neon, argon, krypton, xenon, and radon. Due to the fully occupied outer electron shell, the elements are chemically very inert (“inert”). They are gaseous at room temperature because they all have very low boiling points.
What do lithium and sodium have in common in atomic structure?
One property that can be exploited to identify alkali metals in their compounds is their flame color. Lithium colors the Bunsen burner flame a deep red, sodium colors it yellow, potassium and rubidium purple, and cesium blue (Fig. 5).
What do the elements of the 2 period have in common?
Second Period: 3Lithium to 10Neon This is followed by 6Carbon, 7Nitrogen, 8Oxygen, 9Fluorine and 10Neon.
What are the properties of the halogens?
Halogens are very reactive nonmetals because they only lack one valence electron to fully occupy the valence shell. Because the halogen-halogen bond is not very stable, halogen molecules also react violently. Like electronegativity, reactivity decreases from fluorine to iodine.
What do the atoms of the 2 main groups have in common?
The 2nd main group, the alkaline earth metals, includes the elements beryllium, magnesium, calcium, strontium, barium and radium. They are all light metals. The light metals are bivalent and (apart from Be) are present in the compounds as doubly positive cations.
What do the atoms of the 3 group have in common?
Main group have three outer electrons, so their valence electron configuration is ns 2 np 1 ( n = 2 − 6 ) . The elements of the 3rd main group differ from each other more than the alkali metals or the alkaline earth metals differ from each other. So is boron, the first element of the 3rd
Why are alkaline earth metals called alkaline earth metals?
Origin of the name: As with the alkali metals, the name “alkaline earth metals” is derived from the alkaline reaction of these metals. They are called alkaline earth metals because they are involved in the structure of the earth’s crust in particularly large quantities.
What are alkali metals and alkaline earth metals?
The metals of the first (alkaline metals) and second main group (alkaline earth metals) of the periodic table are very reactive substances whose compounds are important basic materials for the chemical industry and are also familiar to us from everyday life, e.g. sodium chloride (common salt) and potassium chloride (dietary salt).
What are the properties of alkali metals?
Properties. Alkaline metals are metallically shiny, silvery-white (exception: cesium has a golden hue with the slightest contamination), soft light metals. They can be cut with a knife. Alkali metals have a low density.
Are alkaline earth metals metals?
The chemical elements beryllium, magnesium, calcium, strontium, barium and radium from the 2nd main group of the periodic table are called alkaline earth metals. They are shiny, reactive metals that have two electrons in their valence shell.
What are the properties of alkaline earth metals?
➢ Unlike the salts of the alkali metals, many of the alkaline earth metals are only slightly soluble in water. ➢ They have melting points between 649°C (magnesium) and 1278°C (beryllium) and boiling points between 1107°C (magnesium) and 2970°C (beryllium). They therefore generally have a higher melting point than the alkali metals.
What happens when you put magnesium in water?
Magnesium burns even when there is no oxygen left. It then combines with nitrogen from the air to form magnesium nitride (Mg3N2). When trying to extinguish with water, it reacts aggressively with the released hydrogen gas.
How do alkaline earth metals react with water?
Reaction with water: Like aluminum, beryllium is passivated in water. Magnesium is also passivated, but the passivation layer dissolves in hot water. The remaining alkaline earth metals react violently with water at room temperature.
Which alkaline earth metal is toxic to humans?
Soluble barium salts are also very toxic, as little as 0.5-0.8 barium chloride can be fatal if taken orally! All alkaline earth metals are highly reactive substances that react with many other elements and compounds.
Is magnesium radioactive?
Of the 22 known isotopes of magnesium, 3 occur as stable nuclei in nature: 24magnesium, 25magnesium and 26magnesium. All other magnesium isotopes are unstable radionuclides, of which 28Mg is the longest-lived with a half-life of approximately 21 hours.
What liquid are barium and strontium stored in?
Chemically it resembles calcium. It oxidizes very easily in air and must therefore be stored under petroleum (or other oxygen-free liquids). Barium is decomposed by water and ethanol.
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