lks isoton nepsr
DESCRIPTION
Lks Isoton NepsrTRANSCRIPT
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LEMBAR KERJA SISWA
Nama :
Kelas :
Kerjakan soal-soal berikut!
1. Tentukan jumlah partikel proton, elektron dan neutron masing masing unsur
berikut
Notasi Atom Nomor
atom
Nomor
massa Proton Elektron Neutron
14
20
22
54
2. Isilah tabel berikut beserta notasi yang sesuai !
Lambang
Nomor
Massa
Nomor
atom
Proton 5 17 86
Neutron 6 16 18 136
Elektron 5 18
Muatan total
+2 3 -2 0
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2
3. Perhatikan lambang atom beberapa unsur berikut:
, ,
, ,
, ,
, ,
, ,
Dari unsur tersebut diatas kelompokkan unsur-unsur yang seisotop, isoton,
isobar dan jelaskan mengapa unsur-unsur tersebut dikatakan sebagai isotop,
isoton,isobar dan isoelektron!
Kelompok Unsur penjelasan
Isotop
Isoton
Isobar
isoelektron
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4. Massa atom dari adalah 35 dengan kelimpahannya 75% dan massa
atom adalah 36,956 dengan kelimpahan 25%. Berdasarkan data
tersebut tentukan massa atom relatif dari klorin adalah ...........................
Diketahui:
Massa isotop-1 = 35
Massa isotop-2 = . . .
% kelimpahan isotop-1 = 75%
% kelimpahan isotop-2 = . . .
Ditanya : massa atom relatif (Ar) atom clorin (Cl)?
Jawab :
1. Cari massa rata-rata atom
Massa rata-rata atom = % kelimpahan x massa isotop-1 + %kelimpahan x
massa isotop-2 + dst............
Maka massa rata-rata atom Cl adalah:
= % kelimpahan x massa isotop-1 + %kelimpahan x massa isotop-2
= . . . . . X . . . . . + . . . . . X . . . . .
= . . . . . + . . . . .
= . . . . . sma
2. Cari massa atom relatif
Ar =
Ar Cl =
Ar Cl = .......
5. Bila massa atom relatif Li adalah 6,941 dan massa atom dan
berturut
turut 6,0151 dan 7,0160, tentukan kelimpahan kedua isotop tersebut di
alam.
Diketahui:
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Ditanya: ...........................................................................................................
Jawab: .............................................................................................................
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6. Perhatikan gambar spektrum massa isotop kalium, K 39 dan K 40 berikut :
Dari data di atas, tentukan kelimpahan ( % ) isotop K 39 dan K 41 jika Ar
K = 39,0983
Diketahui:
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Ditanya: ...........................................................................................................
Jawab: .............................................................................................................
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38,9637 sma
40,974 sma
39 40 41
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7. Lengkapi tabel berikut:
No. Nama
Unsur
No.
Atom
Kulit
K
n=1
L
n=2
M
n=3
N
n=4
1 Natrium 11
2 Magnesium 12 8
3 Kalium 19
4 Argon 18 2
5 Kripton 36 18
8. Lengkapi tabel berikut!
No. No.
Atom
Kulit Elektron
valensi K
n=1
L
n=2
M
n=3
N
n=4
1 13 2 8 3 3
2 15 2 8 5 5
3 19
4 18
5 36
Dari tabel diatas simpulkan apa yang dimaksud dengan elektron valensi ........
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