Atomic structure：

1、new way chemistry for hong kong a-level book 11 new way chemistry for hong kong a-level book 12 new way chemistry for hong kong a-level book 13 1.1 the atomic nature of matter (sb p.2) the greek philosopher democritus new way chemistry for hong kong a-level book 14 iron continuous division continuou

2、s division 1.1 the atomic nature of matter (sb p.2) these are iron atoms! new way chemistry for hong kong a-level book 15 john dalton proposed his daltons atomic theory 1.1 the atomic nature of matter (sb p.2) new way chemistry for hong kong a-level book 16 1.1 the atomic nature of matter (sb p.2) 5

3、. atoms of different 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 ch

4、emical properties. 4.atoms of different elements are different. they have different masses and chemical properties. new way chemistry for hong kong a-level book 17 new way chemistry for hong kong a-level book 18 1.2 the experimental evidence of atomic structure (sb p.3) a beam of rays came out from

5、the cathode and hit the anode he called the beam cathode rays new way chemistry for hong kong a-level book 19 1.2 the experimental evidence of atomic structure (sb p.4) the beam was composed of negatively charged fast-moving particles. deflected in the electric field deflected in the magnetic field

6、new way chemistry for hong kong a-level book 110 1.2 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 tube the particles were constituents of all atoms! he called the parti

7、cles electrons. new way chemistry for hong kong a-level book 111 1.2 the experimental evidence of atomic structure (sb p.4) atom an atom is electrically neutral no. of positively charged particles = no. of negatively charged particles new way chemistry for hong kong a-level book 112 1.2 the experime

8、ntal evidence of atomic structure (sb p.4) + + + + + + positive charge an atom was a positively charged sphere negatively charged electrons embedded in it like a raisin pudding electron new way chemistry for hong kong a-level book 113 1.2 the experimental evidence of atomic structure (sb p.4) perfor

9、med by ernest rutherford new way chemistry for hong kong a-level book 114 1.2 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 -par

10、ticles were scattered or rebounded back new way chemistry for hong kong a-level book 115 1.2 the experimental evidence of atomic structure (sb p.5) the condensed core is called nucleus the positively charged particle is called proton new way chemistry for hong kong a-level book 116 1.2 the experimen

11、tal evidence of atomic structure (sb p.5) expectation: mass of atom = total mass of protons mass of atom total mass of protons new way chemistry for hong kong a-level book 117 1.2 the experimental evidence of atomic structure (sb p.5) presence of neutrons proved by james chadwick new way chemistry f

12、or hong kong a-level book 118 1.2 the experimental evidence of atomic structure (sb p.5) proton electron neutron new way chemistry for hong kong a-level book 119 new way chemistry for hong kong a-level book 120 1.3 sub-atomic particles (sb p.6) 3 kinds of sub-atomic particles: protons neutrons elect

13、rons inside the condensed nucleus moving around the nucleus new way chemistry for hong kong a-level book 121 1.3 sub-atomic particles (sb p.7) new way chemistry for hong kong a-level book 122 1.3 sub-atomic particles (sb p.6) sub-atomic particle protonneutronelectron symbolp orn ore- or location in

14、atom nucleusnucleussurrounding the nucleus actual charge (c) 1.6 10-901.6 x 10-9 relative charge+10-1 actual mass (g)1.7 10-241.7 10-249.1 10-28 approximate relative mass (a.m.u.) 110 h 1 1 n 1 0 e 0 -1 new way chemistry for hong kong a-level book 123 1.3 sub-atomic particles (sb p.6) new way chemis

15、try for hong kong a-level book 124 new way chemistry for hong kong a-level book 125 1.4 atomic number, mass 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 protons number of electrons = reason:

16、atoms are electrically neutral. why? new way chemistry for hong kong a-level book 126 1.4 atomic number, mass number 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 protons number of neutrons + new way chem

17、istry for hong kong a-level book 127 1.4 atomic number, mass number and isotopes (sb p.8) atomno. of protons no. of electrons no. of neutrons atomic number mass number hydrogen1101(1 + 0) = 1 oxygen8888(8 + 8) = 16 argon18182218(18+22) = 40 new way chemistry for hong kong a-level book 128 1.4 atomic

18、 number, mass number and isotopes (sb p.8) isotopes are atoms of the same element with the same number of protons but different numbers of neutrons. representation: x a z symbol of the element mass number atomic number new way chemistry for hong kong a-level book 129 1.4 atomic number, mass number a

19、nd isotopes (sb p.8) e.g. the two isotopes of chlorine are written as: cl 35 17 cl 37 17 or labelled as cl-35 and cl-37. new way chemistry for hong kong a-level book 130 1.4 atomic number, mass number and isotopes (sb p.9) elementisotopeatomic number no. of protons no. of neutrons natural abundanc e

20、 (%) hydrogen11099.8 1110.02 carbon66698.89 6671.11 668trace h 1 1 h 2 1 c 12 6 c 13 6 c 14 6 new way chemistry for hong kong a-level book 131 new way chemistry for hong kong a-level book 132 1.5 mass spectrometer (sb p.10) a highly accurate instrument! new way chemistry for hong kong a-level book 1

21、33 1.5 mass spectrometer (sb p.10) new way chemistry for hong kong a-level book 134 1.8 mass spectrometer (sb p.21) m/e ratiocorresponding ion 35 35cl+ 37 37cl+ 70 35cl35cl+ 72 35cl 37cl+ 74 37cl 37cl+ new way chemistry for hong kong a-level book 135 m/e ratiocorresponding ion 35 35cl+ 37 37cl+ 50 1

22、2ch335cl+ 51 13ch3 37cl+ 52 12ch3 37cl+ 1.8 mass spectrometer (sb p.21) new way chemistry for hong kong a-level book 136 new way chemistry for hong kong a-level book 137 1.9 relative isotopic, atomic and molecular masses (sb p.22) the relative isotopic mass of a particular isotope of an element is t

23、he relative mass of one atom of that isotope on the carbon-12 scale. e.g. relative isotopic mass of cl-35 = 35 relative isotopic mass of cl-37 = 37 new way chemistry for hong kong a-level book 138 1.9 relative isotopic, atomic and molecular masses (sb p.22) mg has the same mass as two c-12 atoms use

24、 carbon-12 as the reference standard new way chemistry for hong kong a-level book 139 the relative atomic mass of an element is the weighted average of the relative isotopic masses of its natural isotopes on the carbon-12 scale. 1.9 relative isotopic, atomic and molecular masses (sb p.23) new way ch

25、emistry for hong kong a-level book 140 1.9 relative isotopic, atomic and molecular masses (sb p.23) the relative abundances of cl-35 and cl-37 are 75.77 and 24.23 respectively relative atomic mass of cl = = 35.48 24.23)(75.55 24.23)(3775.77)(35 new way chemistry for hong kong a-level book 141 1.9 re

26、lative 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 142 1.9 relative isotopic, atomic and molecular masses (sb p.23) what is the relative molecular mass of ch3cl? re

27、lative molecular mass of ch3cl = = 50.50 40)2(123 40)(522)(51123)(50 new way chemistry for hong kong a-level book 143 the end new way chemistry for hong kong a-level book 144 (a) what does the word “atom” literally mean? (b) which point of daltons atomic theory is based on the law of conservation of

28、 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 states that all pure samples of the same chemical c

29、ompound 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 numbers of various atoms combined bear a simpl

30、e whole number ratio to each other. back answer new 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 experiments: (i) e. goldsteins gas discharge tube ex

31、periment; (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 electrons (iii) discovery of nucleus in atom

32、s back answer new way chemistry for hong kong a-level book 146 the identity of an element is determined by the number of which sub-atomic particle? back 1.3 sub-atomic particles (sb p.6) the identity of an element is determined by the number of protons in its atomic nucleus. answer new way chemistry

33、 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) electron back answer new way chemistry for hong kong a-level book 148 are

34、 there any sub-atomic particles other than protons, neutrons and electrons? back 1.3 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 quark. answer new

35、 way chemistry for hong kong a-level book 149 if bromine has two isotopes, 79br and 81br, how many physically distinguishable combinations of br atoms are there in br2? back 1.3 sub-atomic particles (sb p.7) there are three physically distinguishable combinations of br atoms (79br79br, 79br81br and

36、81br81br) in br2. answer new way chemistry for hong kong a-level book 150 write 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.na 23 11 answer new way chemistry for hong kong a-level book 151 label the different parts of the mass spectrometer. 1.5 mass spectrometer (sb p.12) back a vaporization chamber b ionization chamber c accelerating electric field d def