Answer:
II and IV.
Explanation:
I. (INCORRECT). A model is a tentative to determinate a thing that can't be proved, and it's made based on evidence. If the model can explain the observation in nature, it is considered right, although it can be proved by a theory.
II. (CORRECT). The most accepted model of atoms says that they're formed by tiny particles, protons, neutrons, and electrons, with the first two on the nucleus, and the other surrounding it in an open space.
III. (INCORRECT). A heterogeneous mixture is a mixture of substances that is possible to identify phases of them, such as in oil and water. In the air, isn't possible to identify the constituents, and it's a homogeneous mixture.
IV. (CORRECT). Silver has atomic number 47, which is its number of protons. The atomic mass is the sum of protons and neutrons, so the number of neutrons is 108 - 47 = 61.
Answer:
Sn and Ge
Explanation:
To obtain the more metallic element, we compare the group in which both elements are. Generally the element with the lower ionzation energy is he more metallic one.
Ionization energy increases fro left to right across a period. Ionization energy decreases down the group.
1. When comparing the two elements A s and S n , the more metallic element is ______based on periodic trends alone.
Sn has a lower ionization energy so it is the more metallic one.
2. When comparing the two elements G e and S b , the more metallic element is ________ based on periodic trends alone.
Ge has a lower ionizaiton energy compared to Sb. So it is more metallic element than Sb.
Answer:
The box will move towards me by the additional force of 60N.
Explanation:
I am pulling the box with a force of 30N and my friend is pushing the box in the same direction with a force of 30N.
Here two forces are exhibited in the same direction that is towards myself as a result the box will move towards me by an additional force of 30N+30N=60N.
