Explanation:
In a physical change, the mass remains constant.
Hence the mass of the ice is the same as the water, which is 20g.
<u>Answer:</u> The tendency of an element to react is closely related to the number of valence electrons in the element.
<u>Explanation:</u>
Chemical reactivity is defined as the tendency of an element to loose of gain electrons.
Metals tend to loose electrons and so their chemical reactivity is the tendency to loose electrons.
Non-metals tend to gain electrons and so their chemical reactivity is the tendency to gain electrons.
The number of electrons that an element will loose or gain depends on the number of valence electrons present around that element.
<u>For Example:</u> Chlorine has 7 valence electrons and need 1 electron to complete its octet, whereas sulfur has 6 valence electrons and need 2 electrons to complete its octet.
So, chlorine will gain 1 electron easily than sulfur and thus, is more reactive than sulfur.
Hence, the tendency of an element to react is closely related to the number of valence electrons in the element.
40 electrons
Explanation:
The N for silicon tetrachloride, SiCl₄ is 40 electrons. The needed electrons that would be used to complete the lewis structure of the compound is actually 40 electrons. This number of electron will help the compound attain a noble configuration.
- The compound SiCl₄ is a covalent one. Here, there is sharing of electrons between two atoms.
- In drawing the electron dot formula, one must take into account the Available electrons and the Needed electrons.
- The Available electrons are sum of the valence electrons that can be accessed for the bonding. Si has 4 valence electrons, Cl has 7 valence electrons this makes a total of 4 + 7(4 atoms of chlorine), 32 available electrons.
- But to make a complete octet like that of noble gases, each atom most have 8 complete outer most electrons. This is the needed number of electrons. Since there are 5 atoms i.e 4 atoms of chlorine and 1 atom of Silicon, the needed electrons will be 5x8 = 40 electrons.
Learn more:
lewis structure : brainly.com/question/6215269
#learnwithBrainly
Answer:
Explanation:
1. Add the atomic mass of all the elements.
39+55.8+12+14= 120.8
2.Divide atomic mass of potassium by total atomic mass
2. Multiply by 100
%32.3
