1.
Menurut Demokritus, suatu materi bersifat diskontinu, artinya . . . .
Correct Answer
C. Dapat dibelah tetapi suatu saat akan berhenti
Explanation
Menurut Demokritus, suatu materi bersifat diskontinu, yang berarti bahwa materi dapat dibelah tetapi suatu saat akan berhenti. Ini berarti bahwa materi terdiri dari partikel-partikel yang disebut atom, yang tidak dapat terus-menerus dibelah menjadi bagian yang lebih kecil. Pada suatu titik, pemisahan materi akan mencapai batas atomik di mana materi tidak dapat lagi dibelah menjadi bagian yang lebih kecil.
2.
Kelemahan model atom Rutherford adalah. . . .
Correct Answer
A. Belum bisa menerangkan alasan elektron tidak tertarik ke inti
Explanation
The weakness of the Rutherford atomic model is that it cannot explain why electrons are not attracted to the nucleus.
3.
Ketiga zat yang termasuk senyawa di bawah ini adalah ....
Correct Answer
B. Karbondioksioda, air dan garam
Explanation
The correct answer is "karbondioksioda, air dan garam". This is because karbondioksida (carbon dioxide), air (water), and garam (salt) are all compounds. Compounds are substances made up of two or more elements that are chemically bonded together. In this case, carbon dioxide is composed of carbon and oxygen, water is composed of hydrogen and oxygen, and salt is composed of sodium and chlorine. Therefore, these three options consist of compounds, while the other options consist of either elements or mixtures.
4.
Perhatikan perubahan zat di bawah ini!1. besi berkarat 4. lilin terbakar2. singkong menjadi tape 5. es mencair3. benang menjadi kainPerubahan zat yang tergolong perubahan kimia adalah ....
Correct Answer
B. 1 dan 4
Explanation
Perubahan zat yang tergolong perubahan kimia adalah besi berkarat dan lilin terbakar. Dalam perubahan kimia, zat-zat mengalami perubahan dalam struktur dan komposisi kimianya sehingga membentuk zat baru dengan sifat-sifat yang berbeda. Pada kasus ini, besi mengalami oksidasi dan membentuk karat, sementara lilin terbakar mengalami reaksi pembakaran dan menghasilkan gas dan abu baru.
5.
Berikut yang merupakan cabang dari ilmu kimia adalah ...
Correct Answer
B. Farmakologi
Explanation
Farmakologi adalah cabang ilmu kimia yang mempelajari tentang obat-obatan, termasuk penelitian tentang sifat-sifat, efek, serta penggunaan obat-obatan tersebut. Dalam ilmu kimia, farmakologi berfokus pada interaksi antara obat dengan tubuh manusia, termasuk proses penyerapan, distribusi, metabolisme, dan eliminasi obat. Dengan demikian, farmakologi merupakan cabang ilmu kimia yang berhubungan langsung dengan penggunaan obat-obatan untuk tujuan medis.
6.
Zat yang merupakan larutan di bawah ini adalah....
Correct Answer
A. Sirup
Explanation
The correct answer is sirup because it is mentioned in the question that "Zat yang merupakan larutan di bawah ini adalah" which translates to "The substance that is a solution below is". Among the given options, sirup is the only substance that can be a solution.
7.
Yang bukan sifat fisika di bawah ini adalah ....
Correct Answer
D. Kereaktifan
Explanation
Kereaktifan merupakan sifat kimia bukan sifat fisika. Sifat fisika melibatkan karakteristik fisik suatu zat seperti kekerasan, kerapatan, dan daya hantar listrik. Kereaktifan, di sisi lain, mengacu pada kemampuan suatu zat untuk bereaksi dengan zat lain.
8.
Teori atom Dalton meliputi pernyataan-pernyataan berikut, kecuali . . . .
Correct Answer
B. Atom mengandung elektron, proton, dan netron
Explanation
Dalton's atomic theory states that each element is composed of indivisible particles called atoms, different elements have different types of atoms, chemical reactions involve the rearrangement of atoms, and different elements combine to form compounds in simple ratios. The statement "atom mengandung elektron, proton, dan netron" (atoms contain electrons, protons, and neutrons) is consistent with Dalton's atomic theory and therefore is not excluded.
9.
Dalam teori atom J.J. Thomson, muatan negatif terletak secara . . . .
Correct Answer
D. Menyebar
Explanation
According to J.J. Thomson's atomic theory, negative charges are spread out or scattered within the atom. This means that the negative charges are not concentrated in one specific area but are distributed throughout the atom.
10.
Teori atom Rutherford merupakan hasil percobaan menembak lapisan tipis emas dengan . . . .
Correct Answer
A. Partikel-α
Explanation
The correct answer is "partikel-α". This is because the Rutherford atomic theory was developed based on experiments that involved bombarding a thin layer of gold with alpha particles. Rutherford's experiment showed that most of the alpha particles passed through the gold foil, indicating that atoms are mostly empty space. However, a few alpha particles were deflected at large angles, suggesting the presence of a small, dense nucleus in the atom. This experiment provided evidence for the existence of a nucleus and led to the development of the Rutherford atomic model.
11.
Partikel neutron dalam atom ditemukan oleh . . . .
Correct Answer
A. J. Chadwick
Explanation
J. Chadwick is the correct answer because he was the scientist who discovered the neutron in the atom. Neutrons are subatomic particles that have no charge and are found in the nucleus of an atom. Chadwick's discovery of the neutron in 1932 was crucial in understanding the structure of the atom and led to advancements in nuclear physics.
12.
Massa partikel yang terbesar dimiliki oleh....
Correct Answer
E. Deuteron
Explanation
The deuteron is a particle that consists of a proton and a neutron bound together in a nucleus. It has the largest mass among the given options because it contains both a proton and a neutron, which are both heavier than an electron or a positron. Therefore, the deuteron has the largest mass compared to the other particles mentioned.
13.
Jumlah proton di dalam inti setiap atom suatu unsur dilambangkan dengan . . . .
Correct Answer
A. Nomor atom
Explanation
The correct answer is "nomor atom." The question is asking for the symbol used to represent the number of protons in the nucleus of an atom. The number of protons in an atom's nucleus is known as the atomic number, which is represented by the symbol "nomor atom." This number determines the element's identity and its position on the periodic table.
14.
Jumlah elektron atom unsur natrium adalah...
Correct Answer
D. 11
Explanation
The correct answer is 11 because the atomic number of sodium is 11, which means that it has 11 electrons. The number of electrons in an atom is equal to its atomic number.
15.
Unsur C mempunyai tiga buah isotop, yaitu , , dan atom tersebut berbeda dalam . . . .
Correct Answer
E. Jumlah netron
Explanation
The correct answer is "jumlah netron" (number of neutrons). This is because isotopes are atoms of the same element that have different numbers of neutrons in their nuclei. The number of neutrons determines the mass of the atom, but not its identity as an element. Therefore, the isotopes of element C differ in the number of neutrons they have.
16.
Atom C mempunyai tiga isotop, yaitu: , , dan jumlah kelimpahannya masing-masing isotop di alam 80%, 10%, dan 10%, maka massa atom C adalah
Correct Answer
A. 12,3
Explanation
The correct answer is 12.3 because the question states that the abundance of the isotopes in nature is 80%, 10%, and 10%. The atomic mass of an element is calculated by multiplying the mass of each isotope by its abundance and then adding them together. In this case, the calculation would be (12 x 0.8) + (13 x 0.1) + (14 x 0.1) = 12.3.
17.
Perhatikan lambang berikut : Pasangan atom yang merupakan ISOBAR adalah ....
Correct Answer
B. P dan R
Explanation
The correct answer is P and R. Isobar refers to atoms or ions that have the same mass number but different atomic numbers. In this case, P and R are isobaric because they have the same mass number but different atomic numbers.
18.
Suatu atom dengan nomor massa 65, di dalam intinya terdapat 35 netron. Konfigurasi elektronnya adalah . . . .
Correct Answer
B. 2, 8,18,2
Explanation
The correct answer is 2, 8, 18, 2. This is because the atomic number of an atom is equal to the number of protons in its nucleus. In this case, the atomic number is not given, but the mass number is given as 65. The mass number is equal to the sum of the number of protons and neutrons in the nucleus. Since the number of neutrons is given as 35, we can subtract this from the mass number to find the number of protons, which is 30. The electron configuration of an atom is determined by the number of electrons, which is equal to the number of protons in a neutral atom. Therefore, the electron configuration would be 2, 8, 18, 2.
19.
Elektron valensi atom adalah . . . .
Correct Answer
C. 5
Explanation
The correct answer is 5. This is because the valence electrons of an atom are the electrons in the outermost energy level or shell. The number of valence electrons determines the chemical properties of an element. Since the question is asking for the number of valence electrons, the correct answer is 5.
20.
Massa atom relatif suatu unsur ditentukan oleh . . . .
Correct Answer
A. Massa rata-rata isotopnya
Explanation
The relative atomic mass of an element is determined by the average mass of its isotopes. Isotopes are atoms of the same element that have different numbers of neutrons, resulting in different masses. The relative abundance of each isotope is taken into account when calculating the average mass. Therefore, the correct answer is "massa rata-rata isotopnya."
21.
Elektron dapat pindah dari satu lintasan ke lintasan yang lain dengan menyerap atau melepas energi, dikemukakan oleh
Correct Answer
C. Neils Bohr
Explanation
Neils Bohr suggested that electrons can move from one orbit to another by absorbing or releasing energy. This concept, known as the Bohr model, proposed that electrons exist in specific energy levels or orbits around the nucleus of an atom. These orbits have fixed energy values, and when an electron absorbs or releases energy, it jumps to a higher or lower energy level, respectively. This explanation provided a better understanding of the behavior of electrons in atoms and contributed to the development of quantum mechanics.
22.
Partikel proton ditemukan oleh ilmuwan yang bernama ....
Correct Answer
A. Goldstein
Explanation
Goldstein adalah ilmuwan yang menemukan partikel proton.
23.
Elektron valensi dari atom adalah
Correct Answer
A. 5
Explanation
The correct answer is 5 because the valence electrons of an atom are the electrons in the outermost energy level or shell. In this case, the atom has 5 valence electrons, which indicates that it belongs to Group 15 of the periodic table.
24.
Untuk ; P, Q, R, S dan T masing-masing memiliki nomor atom 5, 7, 9, 11 dan 15 . Atom yang memiliki elektron valensi terbesar adalah ....
Correct Answer
C. R
Explanation
The atom with the largest valence electron is the one with the highest atomic number. In this case, atom R has an atomic number of 9, which is higher than the atomic numbers of atoms P, Q, S, and T. Therefore, atom R has the largest valence electron.
25.
Tembaga di alam terdiri atas isotop Cu-65 (20%) dan isotop Cu-63 (80%), maka massa atom relatif (Ar) tembaga adalah ....
Correct Answer
B. 63,4
Explanation
The relative atomic mass (Ar) of copper can be calculated by taking the weighted average of the masses of its isotopes, based on their abundance. In this case, copper is composed of 20% of Cu-65 and 80% of Cu-63. To calculate the Ar, we can multiply the mass of each isotope by its abundance and then sum the results. (65 x 0.20) + (63 x 0.80) = 13 + 50.4 = 63.4. Therefore, the correct answer is 63.4.