You are watching: Why do elements in a group have similar properties
Key PointsThe physical properties of facets depend in component on their valence electron configurations. As this configuration remains the same within a group, physical properties tfinish to reprimary rather continual.The many significant within-group alters in physical properties take place in Groups 13, 14, and also 15, wright here the aspects at the height are non-metallic, while the facets at the bottom are metals.The fads in boiling and melting points vary from group to group, based upon the kind of non-bonding interactions holding the atoms together.
TermsductileCapable of being pulled or extended into thin wire by mechanical pressure without breaking.physical propertyAny home that is measurable whose value explains a physical system’s state.malleableAble to be hammered right into thin sheets; capable of being extfinished or shaped by beating through a hammer or by the push of rollers.
In chemisattempt, a team is a vertical column in the routine table of the chemical aspects. Tright here are 18 groups in the typical regular table, including the d-block elements however excluding the f-block facets. Each element within a group has actually similar physical or chemical properties bereason of its atom’s outera lot of electron shell (the majority of chemical properties are conquered by the orbital location of the outerthe majority of electron).
Common Physical Properties
A physical residential or commercial property of a pure substance can be defined as anypoint that deserve to be observed without the identification of the substance altering. The observations typically consist of some type of numerical measurement, although sometimes tright here is an extra qualitative (non-numerical) description of the building. Physical properties encompass such points as:ColorBrittlenessMalleabilityDuctilityElectrical conductivityDensityMagnetismHardnessAtomic numberSpecific heatHeat of vaporizationHeat of fusionCrystalline configurationMelting temperatureBoiling temperatureHeat conductivityVapor pressureTendency to dissettle in various liquids
These are just a few of the measurable physical properties.
Within a group of the periodic table, each aspect has the same valence electron configuration. For example, lithium, sodium, potassium, rubidium, cesium, and also francium all have a single electron in an s orbital, whereas eincredibly facet in the team including fluorine has actually the valence electron configuration ns2np5, where n is the period. This implies the facets of a team regularly exhibit equivalent chemical reactivity, and also tbelow might be similarities in physical properties also.
Boiling and Melting Points
Before a conversation of the melting points of miscellaneous facets, it should be listed that some elements exist in various creates. For instance, pure carbon deserve to exist as diamond, which has actually an extremely high melting point, or as graphite, whose melting allude is still high yet a lot reduced than that of diamond.
Different groups exhibit different patterns in boiling and also melting points. For Groups 1 and 2, the boiling and melting points decrease as you move down the group. For the transition metals, boiling and melting points mostly increase as you relocate dvery own the team, however they decrease for the zinc family members. In the major team facets, the boron and also carbon households (Groups 13 and also 14) decrease in their boiling and melting points as you relocate dvery own the group, whereas the nitrogen, oxygen, and fluorine family members (Groups 15, 16, and also 17) tfinish to boost in both. The noble gases (Group 18) decrease in their boiling and also melting points dvery own the team.
These phenomena have the right to be construed in relation to the types of pressures holding the facets together. For metallic species, the metallic bonding interaction (electron-sharing) becomes even more difficult as the elements get larger (toward the bottom of the table), leading to the pressures holding them together to come to be weaker. As you move appropriate alengthy the table, but, polarizability and also van der Waals interactions predominate, and also as larger atoms are even more polarizable, they tend to exhilittle stronger intermolecular forces and also therefore better melting and boiling points.
Metallic elements are shiny, normally gray or silver in color, and conductive of heat and electrical power. They are malleable (can be hammered into thin sheets) and ductile (deserve to be extended right into wires). Some metals, such as sodium, are soft and also have the right to be reduced via a knife. Others, such as iron, are extremely difficult. Non-metallic atoms are dull and are poor conductors. They are brittle as soon as solid, and also many are gases at STP (standard temperature and pressure). Metals offer amethod their valence electrons as soon as bonding, whereas non-metals tfinish to take electrons.A metal and a non-MetalOn the left is sodium, a very metallic facet (ductile, malleable, conducts electricity). On the ideal is sulfur, a very non-metallic facet.
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Metallic character increases from ideal to left and from top to bottom on the table. Non-metallic character follows the oppowebsite pattern. This is because of the various other trends: ionization energy, electron affinity, and electronegativity. You will certainly notification a jagged line running through the routine table beginning in between boron and also aluminum – this is the separation in between metallic and non-metallic facets, with some elements cshed to the line exhibiting characteristics of each. The metals are towards the left and facility of the regular table, in the s, d, and also f blocks. Poor steels and metalloids (somewhat steel, rather non-metal) are in the lower left of the p block. Non-steels are on the best of the table.
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