Presentation on theme: "In this presentation you will: Properties of an Atom explore the reactivity series explore the bonding of atoms Next > explore the reactivity of different."— Presentation transcript:
In this presentation you will: Properties of an Atom explore the reactivity series explore the bonding of atoms Next > explore the reactivity of different atoms Most reactive Least reactive PotassiumK Sodium Na CalciumCa Magnesium Mg AluminumAl Carbon C Zinc Zn IronFe TinSn LeadPb Hydrogen H CopperCu SilverAg GoldAu PlatinumPt Cl Na + -
Next > In this presentation, you will explore the differing reactivities of elements and look at the trends in reactivity in the halogens and the alkali metals. You will explore the reactivity series and its uses in predicting chemical reactions. You will also explore the different types of bonding that take place between atoms. A + B C + D Introduction
Next > All elements have different properties. Some elements are similar; others display completely different properties. Reactivity
Period Group Next > The periodic table displays the elements, so that they can be categorized into groups and periods that have similar properties. The different properties of different elements lead to each one having a different reactivity. Reactivity
Reactivity is the ability of a substance to react with another chemical substance to produce new products. Elements have varying reactivities, which are related to the electron arrangements within their atoms. Next > Carbon (C) atom Inner electrons Nucleus Energy levels Outer electrons
Reactivity Atoms that have full electron outer energy levels are very unreactive. These electron arrangements are said to be stable. Next > Neon (Ne) Atom (Noble Gas) Elements with full outer energy levels appear in group 18 of the periodic table; they are called the noble gases. Full outer energy level
Question 1 Next > “The reactivity of elements is related to the electron arrangement within their atoms.” Is this statement true or false?
Next > True “The reactivity of elements is related to the electron arrangement within their atoms.” Is this statement true or false? Question 1
Electron Arrangement For any element in the main block of the periodic table, it is easy to work out the electron arrangement within its atoms. The number of energy levels is the same as the period in which the element has been placed. Next > Period For example, sodium in period 3, has three energy levels. Sodium (Na) atom Three energy levels
Electron Arrangement The number of electrons in the outer energy level is normally the same for each group member. Next > For example, all group 1 metals have one electron in the outer energy level. Group One electron in outer energy level Group 18 elements have eight electrons in their outer shell (except helium, which has only two). Sodium (Na) atom
Nearly empty energy level Nearly full energy level Reactivity Very reactive elements have atoms containing nearly empty or nearly full outer energy levels. Next > For example, group 1 (alkali metals) and group 17 (halogens) contain very reactive elements.
Atomic radius Reactivity In both the alkali metals and halogens, each individual element has a different reactivity. Next > Reactivity varies up and down the groups. Increasing Radius This is due to outer electrons becoming further away from the nucleus as the atomic radius increases down each group.
Potassium (K) atom Alkali Metals The alkali metals are a family of very reactive metals. They include sodium (Na), potassium (K), and lithium (Li). Their atoms have one electron in the outer energy level. When they react they lose that electron. Next > one outer electron
Alkali Metals These metals have to be stored in oil to exclude air and water because they will react immediately with both. The reaction with water produces hydrogen gas and an alkali solution. Next > alkali metal + water metal hydroxide + hydrogen Potassium (K) atom one outer electron
Next > Elements in group 1 of the periodic table, the alkali metals, have... Question 2 A) one energy level B) one electron in the outer energy level C)a full outer energy level
Elements in group 1 of the periodic table, the alkali metals, have... Question 2 Next > A) one energy level B) one electron in the outer energy level C)a full outer energy level
Alkali Metals When heated up in air, the alkali metals burn to form white solid oxides. The color given by the flame is characteristic of the metal. Next > LithiumSodiumPotassium
Alkali Metals Next > Most reactive Least reactive This is because, as we go down the group, the outer electrons become further away from the nucleus and so become easier to take away. Potassium reacts more violently than sodium and lithium with both water and oxygen. It is more reactive. Therefore, as you go down the group, the reactivity increases.
Halogens The elements in group 17 of the periodic table are known as the halogens. Halogens are a family of non-metals including fluorine (F), chlorine (Cl), and bromine (Br). The halogens share many chemical and physical similarities. For example, all halogen molecules are diatomic (each one contains two atoms), so their molecular formulas are written as F 2, Cl 2, Br 2, and so on. Next > Fluorine gas, F 2 Bromine liquid, Br 2 Chlorine gas, Cl 2
Halogens The halogens have similar properties because they all have one electron missing from an otherwise full outer energy level. Next > Cl
Halogens Each halogen has a slightly different reactivity. When halogens react, they gain an electron. The closer the outer energy level is to the nucleus, the greater the attraction will be on the gained electron. Reactivity decreases down the group. Most reactive Least reactive Next > This means that the most reactive member of group 17 is fluorine, as the outer energy level is closest to the nucleus.
Question 3 Which one of these halogens is the LEAST reactive? Next > A) Iodine B) Chlorine C) Bromine D) Astatine E) Fluorine
Next > Question 3 A) Iodine B) Chlorine C) Bromine D) Astatine E) Fluorine Which one of these halogens is the LEAST reactive?
The Metal Reactivity Series Scientists have organized the metals in order of reactivity by comparing them in certain reactions, such as: displacement reactions The assembled order is known as the metal reactivity series. Next > reactions with acids and bases reactions with water reactions with oxygen Most reactive Least reactive Potassium K Sodium Na Calcium Ca Magnesium Mg Aluminum Al Carbon C Zinc Zn Iron Fe Tin Sn Lead Pb Hydrogen H Copper Cu Silver Ag Gold Au Platinum Pt
The Metal Reactivity Series The higher the metal in the series, the more reactive it is. This means that it will react faster and more vigorously than the metals below it. It can also displace the metals below it. The metal reactivity series has been assembled by examining the relative reactivities of all metals in the periodic table and comparing them with carbon and hydrogen. Next > Most reactive Least reactive Potassium K Sodium Na Calcium Ca Magnesium Mg Aluminum Al Carbon C Zinc Zn Iron Fe Tin Sn Lead Pb Hydrogen H Copper Cu Silver Ag Gold Au Platinum Pt
The Metal Reactivity Series Next > The metal reactivity series can be used: Carbon and hydrogen are also included in the series as reference points. to predict whether a chemical reaction will take place to predict the relative speed of a chemical reaction Most reactive Least reactive Potassium K Sodium Na Calcium Ca Magnesium Mg Aluminum Al Carbon C Zinc Zn Iron Fe Tin Sn Lead Pb Hydrogen H Copper Cu Silver Ag Gold Au Platinum Pt
Reactivity Series The reactivity of a metal determines its uses. It explains why cutlery is not made from sodium; sodium reacts violently with water and tarnishes immediately once in contact with air. Next > Sodium
Reactivity Series Gold is used for jewelry because it is not very reactive. It does not react readily with oxygen. Next > Gold Gold is a shiny metal that retains its shininess for a long time. This is different to magnesium, for example, which tarnishes when in contact with oxygen.
Bonding When atoms react together, they usually form bonds and combine. A chemical bond is a mechanism that chemically combines atoms. Next > There are two main types of bonding: Ionic Chemical bond A + B AB Covalent
Ionic Bonding Ionic bonding involves the complete transfer of electrons from one atom to another. Next > This causes the formation of oppositely charged ions. One atom loses electrons and becomes positively charged. The other gains electrons and becomes negatively charged. The oppositely charged ions are held together due to the attraction between two opposite charges.
Na Ionic Bonding Sodium chloride is a good example. Sodium has one electron in its outer energy level, and chlorine needs one electron to have a complete outer energy level. Next > Cl
Na Cl Ionic Bonding Therefore, when sodium and chlorine react, each sodium atom loses one electron and forms a positive ion. Each chlorine atom gains one electron and forms a negatively charged ion. The ions are held together as opposite charges attract. This ionic bond makes the compound sodium chloride. Next > Na + Cl NaCl + - Na + Cl -
Covalent Bonding Covalent bonding involves the sharing of electrons, rather than their complete transfer. The outer electron energy levels overlap, sharing the electrons between the atoms. Next > Shared electrons due to overlap of energy levels Single Bond AB BA
Covalent Bonding One pair, two pairs, or even three pairs of electrons can be shared, forming single, double, or triple bonds. Next > This type of bonding usually occurs between non-metallic elements. Double Bond AB BA
Covalent Bonding An example is chlorine gas, Cl 2. Each chlorine atom has seven electrons in its outer energy level. However, it needs eight to be a completely full level. One electron from each atom is donated to form a pair of electrons. The pair of electrons is shared between both atoms. This bond holds them together. It is called a single covalent bond. Next > Single covalent bond Cl
“Covalent bonding involves complete transfer of electrons from one atom to another.” Is this statement true or false? Question 4
Next > False “Covalent bonding involves complete transfer of electrons from one atom to another.” Is this statement true or false?
Summary In this presentation you have seen: End that each element has a different reactivity. the trends in reactivity within the halogens and alkali metals. the difference between ionic and covalent bonding.