Answer:
.
Explanation:
Based on the electron configuration of this ion, count the number of electrons in this ion in total:
.
Each electron has a charge of 
.
Atoms are neutral and have 
charge. However, when an atom gains one extra electron, it becomes an ion with a charge of . Likewise, when that ion gains another electron, the charge on this ion would become 
.
The ion in this question has a charge of . In other words, this ion is formed after its corresponding atom gains two extra electrons. This ion has 
electrons in total. Therefore, the atom would have initially contained 
electrons. The atomic number of this atom would be 
.
Refer to a modern copy of the periodic table. The element with an atomic number of is sulphur with atomic symbol 
. To denote the ion, place the charge written backwards ("
" for a charge of ) as the superscript of the atomic symbol:
.
Answer:
The elements in group 13 and group 15 form a cation with a -3 charge each.
B. Theory
The hypothesis that stand the test of time (often tested and never rejected) is called theory. A theory is supported by a great dealcof evidence.
The answer is D, far apart and have weak attractive forces between them. The ideal gas means that the volume of molecule and the forces between them can be ignored.
<u>Given</u> :
- Amount = 20 kg
- Heat energy absorbed = 237,000 J
- Temperature change = 15 °C
<u>Formula applied</u> :
- Q = absorbed heat
- m = mass
- c = specific heat capacity
- ΔT = temperature change
Let's solve for c !
⇒ 237,000 = 20 × c × 15
⇒ c = 237,000 ÷ 300
⇒ 
∴ The specific heat capacity of granite is <u>790 J kg⁻¹ K⁻¹</u>.
