Atomic structure：

1、new way chemistry for hong kong a-level book 11new way chemistry for hong kong a-level book 12new way chemistry for hong kong a-level book 131.1 the atomic nature of matter (sb p.2)the greek philosopher democritusnew way chemistry for hong kong a-level book 14ironcontinuous divisioncontinuous divisi

2、on1.1 the atomic nature of matter (sb p.2)these are iron atoms!new way chemistry for hong kong a-level book 15john dalton proposed his daltons atomic theory1.1 the atomic nature of matter (sb p.2)new way chemistry for hong kong a-level book 161.1 the atomic nature of matter (sb p.2)5. atoms of diffe

3、rent elements combine to form a compound. the numbers of various atoms combined bear a simple whole number ratio to each other.1.all elements are made up of atoms.2.atoms can neither be created nor destroyed.3.atoms of the same element are identical. they have the same mass and chemical properties.4

4、.atoms of different elements are different. they have different masses and chemical properties.new way chemistry for hong kong a-level book 17new way chemistry for hong kong a-level book 181.2 the experimental evidence of atomic structure (sb p.3) a beam of rays came out from the cathode and hit the

5、 anode he called the beam cathode raysnew way chemistry for hong kong a-level book 191.2 the experimental evidence of atomic structure (sb p.4)the beam was composed of negatively charged fast-moving particles.deflected in the electric fielddeflected in the magnetic fieldnew way chemistry for hong ko

6、ng a-level book 1101.2 the experimental evidence of atomic structure (sb p.4)measure the mass to charge ratio (m/e) of the particles producedindependent of the nature of the gas inside the discharge tubethe particles were constituents of all atoms!he called the particles electrons.new way chemistry

7、for hong kong a-level book 1111.2 the experimental evidence of atomic structure (sb p.4)atoman atom is electrically neutralno. of positively charged particles = no. of negatively charged particles new way chemistry for hong kong a-level book 1121.2 the experimental evidence of atomic structure (sb p

8、.4)+positive charge an atom was a positively charged sphere negatively charged electrons embedded in it like a raisin pudding electronnew way chemistry for hong kong a-level book 1131.2 the experimental evidence of atomic structure (sb p.4) performed by ernest rutherfordnew way chemistry for hong ko

9、ng a-level book 1141.2 the experimental evidence of atomic structure (sb p.4) he bombarded a thin gold foil with a beam of fast-moving -particles (+ve charged)observation: most -particles passed through the foil without deflection very few -particles were scattered or rebounded backnew way chemistry

10、 for hong kong a-level book 1151.2 the experimental evidence of atomic structure (sb p.5) the condensed core is called nucleus the positively charged particle is called protonnew way chemistry for hong kong a-level book 1161.2 the experimental evidence of atomic structure (sb p.5)expectation:mass of

11、 atom = total mass of protonsmass of atom total mass of protonsnew way chemistry for hong kong a-level book 1171.2 the experimental evidence of atomic structure (sb p.5) presence of neutrons proved by james chadwicknew way chemistry for hong kong a-level book 1181.2 the experimental evidence of atom

12、ic structure (sb p.5)protonelectronneutronnew way chemistry for hong kong a-level book 119new way chemistry for hong kong a-level book 1201.3 sub-atomic particles (sb p.6)3 kinds of sub-atomic particles: protons neutrons electronsinside the condensed nucleusmoving around the nucleusnew way chemistry

13、 for hong kong a-level book 1211.3 sub-atomic particles (sb p.7)new way chemistry for hong kong a-level book 1221.3 sub-atomic particles (sb p.6)sub-atomic particleprotonneutronelectronsymbolp orn ore- orlocation in atomnucleusnucleussurrounding the nucleusactual charge (c)1.6 10-901.6 x 10-9relativ

14、e charge+10-1actual mass (g)1.7 10-241.7 10-249.1 10-28approximate relative mass (a.m.u.)110h11n10e0-1new way chemistry for hong kong a-level book 1231.3 sub-atomic particles (sb p.6)new way chemistry for hong kong a-level book 124new way chemistry for hong kong a-level book 1251.4 atomic number, ma

15、ss number and isotopes (sb p.7)the atomic number (z) of an element is the number of protons contained in the nucleus of the atom.atomic number=number of protonsnumber of electrons=reason: atoms are electrically neutral.why?new way chemistry for hong kong a-level book 1261.4 atomic number, mass numbe

16、r and isotopes (sb p.8)the mass number (a) of an atom is the sum of the number of protons and neutrons in the nucleus.mass number=number of protonsnumber of neutrons+new way chemistry for hong kong a-level book 1271.4 atomic number, mass number and isotopes (sb p.8)atomno. of protonsno. of electrons

17、no. of neutronsatomic numbermass numberhydrogen1101(1 + 0) = 1oxygen8888(8 + 8) = 16 argon18182218(18+22) = 40new way chemistry for hong kong a-level book 1281.4 atomic number, mass number and isotopes (sb p.8)isotopes are atoms of the same element with the same number of protons but different numbe

18、rs of neutrons.representation:xazsymbol of the elementmass numberatomic numbernew way chemistry for hong kong a-level book 1291.4 atomic number, mass number and isotopes (sb p.8)e.g. the two isotopes of chlorine are written as:cl3517cl3717or labelled as cl-35 and cl-37.new way chemistry for hong kon

19、g a-level book 1301.4 atomic number, mass number and isotopes (sb p.9)elementisotopeatomic numberno. of protonsno. of neutronsnatural abundance (%)hydrogen11099.81110.02carbon66698.896671.11668traceh11h21c126c136c146new way chemistry for hong kong a-level book 131new way chemistry for hong kong a-le

20、vel book 1321.5 mass spectrometer (sb p.10)a highly accurate instrument!new way chemistry for hong kong a-level book 1331.5 mass spectrometer (sb p.10)new way chemistry for hong kong a-level book 1341.8 mass spectrometer (sb p.21)m/e ratiocorresponding ion3535cl+3737cl+7035cl35cl+7235cl 37cl+7437cl

21、37cl+new way chemistry for hong kong a-level book 135m/e ratiocorresponding ion3535cl+3737cl+5012ch335cl+5113ch3 37cl+5212ch3 37cl+1.8 mass spectrometer (sb p.21)new way chemistry for hong kong a-level book 136new way chemistry for hong kong a-level book 1371.9 relative isotopic, atomic and molecula

22、r masses (sb p.22)the relative isotopic mass of a particular isotope of an element is the relative mass of one atom of that isotope on the carbon-12 scale.e.g. relative isotopic mass of cl-35 = 35relative isotopic mass of cl-37 = 37new way chemistry for hong kong a-level book 1381.9 relative isotopi

23、c, atomic and molecular masses (sb p.22)mg has the same mass as two c-12 atomsuse carbon-12 as the reference standardnew way chemistry for hong kong a-level book 139the relative atomic mass of an element is the weighted average of the relative isotopic masses of its natural isotopes on the carbon-12

24、 scale.1.9 relative isotopic, atomic and molecular masses (sb p.23)new way chemistry for hong kong a-level book 1401.9 relative isotopic, atomic and molecular masses (sb p.23)the relative abundances of cl-35 and cl-37 are 75.77 and 24.23 respectivelyrelative atomic mass of cl= 35.4824.23)(75.5524.23

25、)(3775.77)(35new way chemistry for hong kong a-level book 1411.9 relative isotopic, atomic and molecular masses (sb p.23)the relative molecular mass is the relative mass of a molecule on the carbon-12 scale.new way chemistry for hong kong a-level book 1421.9 relative isotopic, atomic and molecular m

26、asses (sb p.23)what is the relative molecular mass of ch3cl?relative molecular mass of ch3cl= 50.5040)2(12340)(522)(51123)(50new way chemistry for hong kong a-level book 143the endnew way chemistry for hong kong a-level book 144(a) what does the word “atom” literally mean?(b) which point of daltons

27、atomic theory is based on the law of conservation of mass proposed by lavoisier in 1774 which states that matter is neither created nor destroyed in the course of a chemical reaction?(c) which point of daltons atomic theory is based on the law of constant proportion proposed by proust in 1799 which

28、states that all pure samples of the same chemical compound contain the same elements combined together in the same proportions by mass?1.1 the atomic nature of matter (sb p.3)(a) indivisible(b) atoms can neither be created nor destroyed.(c) atoms of different elements combine to form a compound. the

29、 numbers of various atoms combined bear a simple whole number ratio to each other.backanswernew way chemistry for hong kong a-level book 145(a) atoms were found to be divisible. what names wer given to the particles found inside the atoms?(b) give the most important point of the following experiment

30、s:(i) e. goldsteins gas discharge tube experiment;(ii)j. j. thomsons cathode ray tube experiment;(iii) e. rutherfords gold foil scattering experiment.1.2 the experimental evidence of atomic structure (sb p.4)(a) electron, proton and neutron(b) (i) discovery of cathode rays (ii) discovery of electron

31、s (iii) discovery of nucleus in atomsbackanswernew way chemistry for hong kong a-level book 146the identity of an element is determined by the number of which sub-atomic particle?back1.3 sub-atomic particles (sb p.6)the identity of an element is determined by the number of protons in its atomic nucl

32、eus.answernew way chemistry for hong kong a-level book 147(a) which part of the atom accounts for almost all the mass of that atom?(b) the mass of which sub-atomic particle is often assumed to be zero?1.3 sub-atomic particles (sb p.7)(a) nucleus(b) electronbackanswernew way chemistry for hong kong a

33、-level book 148are there any sub-atomic particles other than protons, neutrons and electrons?back1.3 sub-atomic particles (sb p.7)other than the three common types of sub-atomic particles (proton, neutron and electron), there are also some sub-atomic particles called positron (anti-electron) and qua

34、rk.answernew way chemistry for hong kong a-level book 149if bromine has two isotopes, 79br and 81br, how many physically distinguishable combinations of br atoms are there in br2?back1.3 sub-atomic particles (sb p.7)there are three physically distinguishable combinations of br atoms (79br79br, 79br8

35、1br and 81br81br) in br2.answernew way chemistry for hong kong a-level book 150write the symbol for the atom that has an atomic number of 11 and a mass number of 23. how many protons, neutrons and electrons does this atom have? 1.4 atomic number, mass number and isotopes (sb p.8)back , 11 protons, 12 neutrons, 11 electrons.na2311answernew way chemistry for hong kong a-level book 151label the different parts of the mass spectrometer.1.5 mass spectrometer (sb p.12)backa vaporization chamberb ionization chamberc accelerating electric fieldd deflectin