Sr or Strontium is s block alkaline earth metal found in the earth’s crust and having monoatomic in nature. Let us discuss about Strontium in detail.
Sr is the next element of calcium, present in the same group but next period and almost the same property as Ca. Sr has a characteristic color of a flame test, which is red in color. So, to detect Sr in other alkaline metal atoms is very easy, it is due to the transition of electrons for the s to d orbital.
It is a soft metal and appears as silver-white yellowish in color which is chemically very reactive. It forms dark oxide layers when exposed to air. Now we will discuss the basic chemical properties of Strontium with proper explanation.
1.Strontium symbol
The atomic symbol is that to express an atom by one or two letters and for a molecule, it should be called a molecular symbol. Let us predict the atomic symbol of Strontium.
The atomic symbol of Strontium is “Sr” as the name start with the English alphabet “Sr”. Because S represents the Sulphur which is present in the oxygen family and St also represent Tin, so we use the first two consecutive of the English alphabet of the Sr to distinguish it from another element.
2. Strontium group in the periodic table
A column of the periodic table where the element is placed by the atomic number is called a group. Let us predict the group of Strontium in the periodic table.
The group of Strontium in the periodic table is 2. Because it is an alkaline earth metal itself, it can easily form di cations by donating two electrons. So, it is placed in the 2nd group as an element.
3. Strontium period in the periodic table
The horizontal rows of the periodic table are called a period and correspond to the successive occupation of orbitals of the valence shell. Now predict the period of the Strontium.
Strontium is belonged to period 5 in the periodic table because it has more than 36 electrons in the valence shell so it is placed in the fifth position of the periodic table in the period and also in the group.
4. Strontium block in the periodic table
The block of the periodic table is known as the set of atomic orbitals of an element where the valence electrons are lying. Let us predict the block of the Strontium.
Strontium is an s block element because the valence electrons present in the orbital is s or the outermost orbital of the Strontium is s, so it belongs to s block element like alkali metals. There are only four blocks present in the periodic table, they are s,p,d, and f according to the orbitals.
5. Strontium atomic number
The number of protons present in the nucleus is called the atomic number of that particular element. Let us find the atomic number of the Strontium.
The atomic number of Strontium is 38, which means it has 38 protons and also it has only 38 electrons because we know the number of protons is always equal to the number of electrons and for this reason, they become neutral due to the neutralization of equal and opposite charges.
6. Strontium atomic Weight
Atomic weight is the mass of one atom of that particular element of the ratio of some standard value. Let us calculate the atomic weight of Strontium.
The atomic weight of hydron on the 12C scale is 87 which means the weight of Strontium is the 87/12th part of the weight of the carbon element. The original atomic weight of Strontium is 87.62, it is because the atomic weight is the average weight of all the isotopes of the element.
7. Strontium Electronegativity according to Pauling
According to Pauling electronegativity is defined as the power of an atom in a molecule to attract electrons to itself. Let us predict the electronegativity of Strontium.
The electronegativity of Strontium according to the Pauling scale is 0.95, which means it is more electropositive in nature and can attract electrons towards itself. The most electronegative atom as per the Pauling scale in the periodic table is fluorine having 4.0 electronegativity.
8. Strontium atomic Density
The atomic density is the number of atoms or nuclides per cm3 or in a unit volume of atoms in a material. Let us calculate the atomic density of Strontium.
The atomic density of Strontium is 2.6 g/cm3 which can be calculated the diving the mass of the Strontium by its volume. Atomic density means the number of atoms present per unit volume but the atomic number is the number of electrons present in the valence and inner orbital.
- Density is calculated by the formula, atomic density = atomic mass / atomic volume.
- The atomic mass or weight of the Strontium atom is 87.62 g
- The volume of the Strontium molecule is 22.4 liter at STP as per Avogardo’s calculation
- So, the atomic density of the Strontium atom is, 87.62/38 = 2.6 g/cm3
9. Strontium melting point
The point where a substance changes its solid state to a liquid or the temperature where the change occurs as atmospheric pressure. Let us find the melting point of the Strontium atom.
The melting point of the Strontium atom is 7770 C or 1050 K temperature because at room temperature Strontium exists as a solid form where all the atoms in the Strontium lie in an ordered manner due to higher energy, so if we increase the temperature then the elements are placed in good arrangement.
10. Strontium boiling point
The boiling point is where the vapor pressure of the substance becomes equal to the atmospheric pressure. Let us find the boiling point of Strontium.
The boiling point of the Strontium atom is 13820 C or 1655K because it exists in solid form at room temperature so the boiling point of the Strontium atom is also very high even at more than 10000 positive temperatures, like iron atom.
The van der Waal’s force of attraction is low so high energy of heat is required for the boiling Strontium. The solid form of Strontium exists at room temperature or higher temperature than its melting point.
11. Strontium Van der Waals radius?
Van der Waal’s radius is the imaginary measurement between two atoms where they are not bound ionically or covalently. Let us find van der Waal’s radius of Strontium.
The van der Waal’s radius of the Strontium molecule is 255 pm because the value is close to the value of which is proposed by Pauling. Van der Waal’s radius is calculated by the mathematical formula considering the distance between two atoms, where atoms are spheres.
- The formula used the find out the Van der Waal’s radius is, Rv = dA-A / 2
- Where RV is the Van Waal’sal’s radius of the molecule
- dA-A is the summation of the radius of two atomic spheres or the distance between the center of two spheres.
12. Strontium ionic radius
Ionic radius is the summation of the radius of cation and anion respectively, for an ionic molecule in a crystal structure. Let us find out the ionic radius of Strontium.
The ionic radius of Strontium is 255 pm is the same as the covalent radius because for Strontium the cation and anion are the same and it is not an ionic molecule, rather it forms by the covalent interaction between two Strontium atoms.
13. Strontium isotopes
The elements that have same number of protons but different numbers of neutrons of substances are called isotopes. Let us discuss the isotopes of Strontium.
Among those only four are stable and naturally occurring isotopes which are discussed below –
- 84Sr
- 86Sr
- 87Sr
- 88Sr
| Isotope | Natural Abundance | Half-life | Emitting particles | No. of Neutron |
| 82Sr | Synthetic | 25.3 days | ε | 44 |
| 83Sr | Synthetic | 1.35 days | β , γ , ε | 45 |
| 84Sr | 0.56% | Stable | N/A | 46 |
| 85Sr | Synthetic | 64.84 days | γ , ε | 47 |
| 86Sr | 9.86% | Stable | N/A | 48 |
| 87Sr | 7.0% | Stable | N/A | 49 |
| 88Sr | 82.58 | Stable | N/A | 50 |
| 89Sr | Synthetic | 50.52 days | β | 51 |
| 90Sr | Trace | 28.90 years | β | 52 |
14. Strontium electronic shell
Electronic shells are those which are surrounding the nucleus and containing a specific number of electrons in it. Let us discuss the electronic shell of Strontium.
The number of electronic shells of Strontium around the nucleus is 8, which is s, p, and d orbitals. Because it has more than 36 electrons and to arrange 18 electrons need 1s,2s,2p, 3s, 3p, 3d, 4s, 4p, and 5s orbital as p orbital contains six electrons and s orbital contains two electrons and d contains 10.
15. Strontium electron configurations
The electronic configuration is an arrangement of the electrons in available orbital by considering Hund’s rule. Let us discuss the electronic configuration of Strontium.
The electronic configuration of Strontium is 1s22s22p63s23p6 3d104s24p65s2 because it has 38 electrons and those electrons should be placed to the nearest orbital of the nucleus s, p, and d orbitals and for the 1st,2nd, 3rd, 4th and 5th orbitals where the principal quantum numbers are 1,2,3, 4, and 5.
- Where the first number stands for the principle quantum number
- The letter is for orbital and the suffix number is the number of electrons.
- But many elements have more principal quantum numbers depending on the number of electrons.
- Kr has 36 electrons, so the remaining electrons are present after noble gas configuration.
- So, it is denoted as [Kr]5s2.
16. Strontium energy of first ionization
The energy required for the removal of the last valence electrons from the respective orbital is called the first ionization energy. Let us predict the first ionization of Strontium.
The energy required for the first ionization of a Strontium atom is 549.5 KJ/mol .The first ionization occurs for Strontium from its s orbital to remove one electron. There is lesser energy required removal of electrons from the 5s orbital which is far away from the nucleus and the force of attraction is low.
Not necessary to remove electrons always for the s orbital, it depends on the valence orbital, if the valence orbital will be p, d or f then the electron is removed from the p, d, and f orbital respectively.
17. Strontium energy of second ionization
Second ionization is the removal of the outermost electron from its +1 oxidation state of the element. Let us see the second ionization of Strontium.
The 2nd ionization energy of Strontium is 1064 KJ/mol because in 2nd ionization electron is removed from the half-filled 5s orbital. So, when an electron is removed from a half-filled orbital then it needs more energy, and also +1 is the stable state for the Sr, so its 2nd ionization is very high than 1st.
After electron removal from electron from the filled 5s then the system will be unstable and energized, so the process is unfavorable, and for this reason, 2nd ionization energy is very high than 1st ionization energy of Strontium.
18. Strontium energy of third ionization
Third ionization is the removal of electrons from the respective orbital having a +2 oxidation state of the element. Let us see the third ionization of Strontium.
The energy required for the third ionization is 4138 KJ/mol. This process occurs for the Strontium from the 4p orbital, and the removal of electrons from the 4p orbital needs more energy because there is the presence of 10 3d electrons which can be shielded the outermost electrons.
19. Strontium oxidation states
The oxidation state is the charge present over the element after the removal of such numbers of an electron to form a stable bond. Let us predict the oxidation state of Strontium.
The stable oxidation state of Strontium is +2 because it has two electrons in the s orbital and when the electron is removed then it can form a stable double bond and gain the noble gas configuration, so it has a +2 oxidation state as the s orbital contains a maximum of two electrons.
20. Strontium CAS number
CAS registry number is a special kind of number a unique unmistakable identifier number provided worldwide. Let us know the CAS number of Strontium.
The CAS number of the Strontium molecule is 7440-24-6, which is given by the chemical abstracts service. Which is different from the CAS number of the other element.
The CAS number of K is unique and not matching with the other element’s CAS number.
21. Strontium ChemSpider ID
The Royal Society of Chemistry gives a particular unique number for every chemical element which is knowns as Chem Spider ID. Let us discuss it for Strontium.
The Chem Spider ID for Strontium is 4514263, which is given by the royal society of chemistry, and by using this number we can evaluate all the chemical data related to the Strontium atom. like CAS number it is also different for all elements.
22. Strontium allotropic forms
Having the same chemical but different physical properties of different structural forms of the same element. Let us discuss the allotropic form of Strontium.
There is no allotropic form of Strontium present in the universe because it does not show catenation properties like carbon.
23. Strontium chemical classification
Chemical classification is the classified the element by its reactive nature, or they cause hazards to the human body. Let us know the chemical classification of Strontium.
Strontium is classified as an alkaline earth metal at room temperature because it can produce heat and electricity also the density of the element is very high and it is more ductile.
24. Strontium state at room temperature
The condition is characterized by the element at room temperature and experimental pressure. Let us predict the state of Strontium at room temperature.
Strontium exists in a solid state at room temperature because it has higher van der Waal’s interaction so the atoms exist very close to each other. The randomness of the atoms is very high at room temperature.
The solid state of the Strontium can be changed to liquid or solid at a very low temperature, where the randomness will be decreased for the Strontium atom.
25. Is Strontium paramagnetic?
The materials tend to get weakly magnetized in the direction of the magnetizing field when placed in a magnetic field. Let us see whether Strontium is paramagnetic or not.
The Strontium atom is diamagnetic in nature, due to the presence of two paired electrons in its 5s orbital, after the first ionization Sr+ is paramagnetic in nature because there will be one unpaired electron for the 5s orbital.
So, we have to check the number of electrons present in the valence orbital for an element whether it is paired form or unpaired form then it will be paramagnetic or diamagnetic accordingly.
Conclusion
Sr is the s block alkaline earth metal that can form a strong base with react in water. That strong base can neutralized stronger acid like sulphuric acid. In the human body almost 99% of Sr present as concentrated form.
Hi……I am Biswarup Chandra Dey, I have completed my Master’s in Chemistry from the Central University of Punjab. My area of specialization is Inorganic Chemistry. Chemistry is not all about reading line by line and memorizing, it is a concept to understand in an easy way and here I am sharing with you the concept about chemistry which I learn because knowledge is worth to share it.
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